## Friday, November 30, 2012

### Phys 102 College Physics II Name:

Phys 102 College Physics II Name: ______________________________________________

Additional Exercises on Chapter 11: Rotational Dynamics and Static Equilibrium

1) A man is holding an 8.00-kg vacuum cleaner at arm's length, a distance of 0.550 m from his shoulder. What is

the torque on the shoulder joint if the arm is horizontal?

A) 4.40 Nm B) 43.2 Nm C) 14.5 Nm D) 0 Nm E) 0.242 Nm

2) A 15.0-kg child is sitting on a playground teeter-totter, 1.50 m from the pivot. What force, applied 0.300 m on

the other side of the pivot, is needed to make the child lift off the ground?

A) 75.0 N B) 66.2 N C) 44.1 N D) 736 N E) 22.5 N

3) The drive chain in a bicycle is applying a torque of 0.850 Nm to the wheel of the bicycle. Treat the wheel as a

hoop with a mass of 0.750 kg and a radius of 33.0 cm. What is the angular acceleration of the wheel?

A) 1.06 rad/s2 B) 20.8 rad/s2 C) 3.43 rad/s2 D) 10.4 rad/s2 E) 5.20 rad/s2

4) In a lab experiment, a student brings up the rotational speed of a rotational motion apparatus to 30.0 rpm. She

then allows the apparatus to slow down on its own, and counts 240 revolutions before the apparatus comes to a

stop. The moment of inertia of the flywheel is 0.0850 kg·m2. What is the retarding torque on the flywheel?

A) 0.000278 Nm

B) 0.0425 Nm

C) 0.0000136 Nm

D) 0.159 Nm

E) 0.0787Nm

Figure 11-5

5) An 82.0 kg-diver stands at the edge of a light 5.00-m diving board, which is supported by two pillars 1.60 m

apart, as shown in Figure 11-5. Find the force exerted by pillar A.

A) 2.51 kN downwards

B) 1.71 kN downwards

C) 3.44 kN upwards

D) 1.71 kN upwards

E) 2.51 kN upwards

1Figure 11-6

6) A store's sign, with a mass of 20.0 kg and 3.00 m long, has its center of gravity at the center of the sign. It is

supported by a loose bolt attached to the wall at one end and by a wire at the other end, as shown in Figure

11-6. The wire makes an angle of 25.0° with the horizontal. What is the tension in the wire?

A) 196 N B) 464 N C) 297 N D) 232 N E) 116 N

Figure 11-7

7) A child is trying to stack two uniform wooden blocks, 12 cm in length, so they will protrude as much as possible

over the edge of a table, without tipping over, as shown in Figure 11-7. What is the maximum possible

overhang distance?

A) 8 cm B) 6 cm C) 9 cm D) 5 cm E) 7 cm

8) A 350-g air track cart on a horizontal air track is attached to a string that goes over a pulley with a moment of

inertia of 6.00 × 10-6 kg·m2 and a radius of 1.35 cm. The string is pulled vertically downward by a force of 2.50

N. What is the acceleration of the cart?

A) 5.27 m/s2 B) 3.27 m/s2 C) 6.53 m/s2 D) 7.14 m/s2 E) 4.98 m/s2

9) A 350-g air track cart on a horizontal air track is attached to a string that goes over a pulley with a moment of

inertia of 6.00 x 10-6 kg·m2 and a radius of 1.35 cm. The string is pulled vertically downward by a force of 2.50

N. What is the tension in the string between the pulley and the cart?

A) 2.50 N B) 2.29 N C) 1.74 N D) 4.58 N E) 1.85 N

210) A mass of 375 g hangs from a string that is wrapped around the circumference of a pulley with a moment of

inertia of 0.0125 kg·m2 and a radius of 26.0 cm. When the mass is released, the mass accelerates downward

and the pulley rotates about its axis as the string unwinds. What is the tension in the string?

A) 1.21 N B) 2.45 N C) 1.84 N D) 0.605 N E) 3.68 N

11) A 330-g air track cart on a horizontal air track is attached to a string that goes over a pulley with a moment of

inertia of 5.00 × 10-6 kg·m2 and a radius of 1.35 cm. A 255 -g mass hangs from the other end of the string and

is released. What is the acceleration of the cart?

A) 6.53 m/s2 B) 4.08 m/s2 C) 7.14 m/s2 D) 4.74 m/s2 E) 9.72 m/s2

12) A mass of 355 g hangs from one end of a string that goes over a pulley with a moment of inertia of

0.0125 kg·m2 and a radius of 15.0 cm. A mass of 680 g hangs from the other end. When the masses are

released, the larger mass accelerates downward, the lighter mass accelerates upward, and the pulley turns

without the string slipping on the pulley. What is the acceleration of the masses?

A) 3.82 m/s2 B) 2.00 m/s2 C) 2.87 m/s2 D) 5.74 m/s2 E) 7.78 m/s2

13) The torque required to turn the crank on an ice cream maker is 4.50 Nm. How much work does it take to turn

the crank through 300 full turns?

A) 8480 J B) 4240 J C) 2700 J D) 1350 J E) 2120 J

Figure 11-9

14) The L-shaped object shown in Figure 11-9 consists of the masses connected by light rods. How much work

must be done to accelerate the object from rest to an angular speed of 3.25 rad/s about the y-axis?

A) 374 J B) 42.2 J C) 173 J D) 27.4 J E) 86.5 J

15) A torque of 0.12 N·m is applied to an egg beater. (a) If the egg beater starts at rest, what is its angular

momentum after 0.50 s? (b) If the moment of inertia of the egg beater is 2.5 x 10-3 kg·m2 what is its angular

speed after 0.50 s?

16) A circular saw blade accelerates from rest to an angular speed of 3620 rpm in 6.30 revolutions. (a) Find the

torque exerted on the saw blade, assuming it is a disk of radius 15.2 cm and mass 0.755 kg. (b) Is the angular

speed of the saw blade after 3.15 revolutions greater than, less than, or equal to 1810 rpm? Explain. (c) Find the

angular speed of the blade after 3.15 revolutions.

3Answer Key

Testname: ADDITIONAL EXERCISES ON CHAPTER 11

1) B

2) D

3) D

4) A

5) B

6) D

7) C

8) C

9) B

10) A

11) B

12) B

13) A

14) C

15) (a) 0.060 kg·m2/s; (b) 24 rad/s

16) (a) 15.8 N·m; (b) greater than; (c) 2560 rev/min

4

### Semester 1 Physics 101 Review Questions

Semester 1 Physics Review Questions

1) Consider the earth, orbiting the sun for a year. Make a comparison between the displacement and the distance the

earth travels.

2) You drive 6.00 km at 50.0 km/h and then another 6.00 km at 90.0 km/h. Your average speed over the 12.0 km

drive will be _________.

3) The slope of a line connecting two points on a position versus time graph represents the objects _______.

4) The slope of a tangent line at a given time on a position versus time graph represent the objects _________

5) The slope of a tangent line at a given time value on a velocity versus time graph gives ________.

6) Define average velocity

7) Define acceleration

8) Suppose that a car traveling to the East (+x direction) begins to slow down as it approaches a traffic light. Make

a statement concerning the direction of its acceleration.

9) The area under the curve of a velocity versus time graph gives represents the object's_________

10) A stone is thrown straight up. When it reaches its highest point, describe the velocity and acceleration of the

stone.

11) Suppose a ball is thrown straight up, reaches a maximum height, then falls to its initial height. Make a

statement about the direction of the velocity and acceleration as the ball is going up.

Figure 2-6

12) Refer to Figure 2-6. If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the

distance you have traveled?

Figure 2-7

13) Figure 2-7 represents the position of a particle as it travels along the x-axis. What is the magnitude of the average

velocity of the particle between t = 1 s and t = 4 s

14) In Figure 2-7 (above), at what value of t is the speed of the particle equal to zero?

Figure 2-10

15) Figure 2-10 shows the velocity-versus-time graph for a basketball player traveling up and down the court in a

straight-line path. Find the net displacement of the player for the 8 s shown on the graph.

16) For figure 2-10, find the acceleration a) from t = 0 sec to t = 2 sec b) from t = 4 sec to t = 8 sec17) An airplane starts from rest and accelerates at 10.8 m/s

2

. What is its speed at the end of a 400. m-long runway?

18) A car is traveling with a constant speed when the driver suddenly applies the brakes, giving the car a deceleration

of 3.50 m/s

2

. If the car comes to a stop in a distance of 30.0 m, what was the car's original speed?

19) An object is thrown upwards with a speed of 14.0 m/s. How long does it take it to reach its maximum height?

20) An object is thrown up with a speed of 14 m/s. How high above the projection point is it after 0.50 s?

21) To determine the height of a bridge above the water, a person drops a stone and measures the time it takes for it

to hit the water. If the time is 2.3 s, what is the height of the bridge?

22) A model rocket rises with constant acceleration to a height of 3.2 m, at which point its speed is 26.0 m/s . How

much time does it take for the rocket to reach this height?

23) A model rocket rises with constant acceleration to a height of 3.2 m, at which point its speed is 26.0 m/s . What

was the magnitude of the rocket's acceleration?

24) Which quantities that we have used this year in Physics are scalar quantities?

25) Which quantities that we have used this year in Physics are vector quantities?

26) A soccer player carries the ball for a distance of 40.0 m in the direction 42.0° west of south. Find the westward

component of the ball's displacement.

27) For general projectile motion, which statement is true when the projectile is at the highest point of its trajectory?

A) The horizontal and vertical components of its velocity are zero.

B) Its velocity and acceleration are both zero.

C) Its velocity is perpendicular to the acceleration.

D) The horizontal component of its velocity is zero.

E) Its acceleration is zero

28) A pilot drops a bomb from a plane flying horizontally at a constant speed. Neglecting air resistance, where will

the horizontal location of the plane be when the bomb hits the ground? (relative to the bomb)

29) A rock is thrown at 60° above the horizontal with a velocity of 40 m/s. It reaches its highest point and starts

falling down. What is the velocity of the rock at the highest point of its trajectory?

30) A student kicks a soccer ball in a high arc toward the opponent's goal. Neglecting air resistance, describe the

velocity and acceleration on its way up in its trajectory.

31) A bullet is fired from ground level with a speed of 150 m/s at an angle 30.0° above the horizontal at a location

where g = 10.0 m/s

2

. What is the vertical component of its velocity when it is at the highest point of its

trajectory?

32) The horizontal and vertical components of the initial velocity of a football are 16 m/s and 20 m/s respectively.

How long does it take for the football to rise to the highest point of its trajectory?

33) A ball is thrown horizontally with an initial velocity of 40 m/s from a height of 10 m. How long will it take for

the ball to touch the ground, neglecting air resistance?

34) A ball rolls over the edge of a building with a horizontal velocity 3.20 m/s. The horizontal range of the ball from

the base of the table is 20.0 m. How tall is the building, neglecting air resistance?

35) A ball is thrown with an initial speed of 60 m/s at an angle of 30° above the horizontal. What is the ball's

horizontal displacement at the end of 4 seconds?

36) A boy kicks a football from ground level with an initial velocity of 20 m/s at an angle of 60° above the

horizontal. What is the horizontal distance to the point where the football hits the ground?37) A boy kicks a football with an initial velocity of 28.0 m/s at an angle of 30.0° above the horizontal. What is the

highest elevation reached by the football in its trajectory?

38) A crow is flying horizontally with a constant speed of 2.70 m/s when it releases a clam from its beak. The clam

lands on the rocky beach 2.10 s later. Just before the clam lands, what is (a) its horizontal component of velocity,

and (b) its vertical component of velocity? (c) its resultant velocity and the angle it makes below the horizontal?

39) In the absence of an external unbalanced force, a moving object will do what as time goes on?

40) An object is moving with constant velocity. a) What can you say about the net force?

b) If there are forces acting on the object, what can you conclude about the forces?

41) When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal velocity.

This means what regarding forces? Draw a FBD

42) A 8000kg truck is towing a 2000kg car. The force exerted by the truck on the car is 6000 N. The force exerted by

the car on the truck is ________.

43) A 0.30 kg ball is thrown up into the air. Ignore air resistance. When it is reaches its maximum height, the net

force acting on it is _______.

44) The elevator in the Space Needle is going down. When the tension pulling up on the elevator is equal to the

elevator's weight, what happens to the motion of the elevator?

45) You ride on an elevator that is moving downward with constant speed while standing on a bathroom scale. How

does the reading on the scale compare to your true weight, mg

46) A block of mass 55kg slides down a frictionless plane inclined at an angle 17° with the horizontal. The normal

force exerted by the plane on the block is?

47) An object rests on an inclined surface. If the inclination of the surface is made steeper, what does the normal force

on the object do?

48) Two objects have masses m and 5m, respectively. They both are placed side by side on a frictionless inclined

plane and allowed to slide down from rest. It takes the heavier object _____times longer/shorter to reach the

bottom of the incline than the lighter.

49) In a particle accelerator, a proton reaches an acceleration of 9.0 x 10

13

m/s

2

. The mass of a proton is

1.7 x 10

-27

kg. What is the net force on the proton?

50) A flatbed truck is carrying a load of timber which is not tied down. The mass of the timber is 899 kg. The

maximum static frictional force between the truck bed and the load is 5488 N. What is the highest acceleration

that the truck can have without losing its load? What is the static coefficient of friction between the load and truck

bed?

51) A 1250 kg boat is pulling a 72 kg water skier on a calm lake. Friction is negligible. The boat accelerates with an

acceleration of 1.3 m/s

2

. What is the force exerted on the skier by the tow rope?

52) A 50.0 kg crate is being pulled along a horizontal frictionless surface. The pulling force is 10.0 N and is directed

20.0° above the horizontal. What is the acceleration of the crate?

53) A 40.0 kg box is being pushed along a horizontal frictionless surface. The pushing force is 15.0 N directed at an

angle of 15.0° below the horizontal. What is the normal force exerted on the crate by the ground?

54) A person has a mass of 45 kg. How much does she weigh? How much less does she weigh on the Moon, where

g = 1.62 m/s

2

?55) A 40.0-kg crate is being lowered by means of a rope. Its downward acceleration is 2.00 m/s

2

. What is the force

exerted by the rope on the crate?

56) A 36.0-kg child steps on a scale in an elevator. The scale reads 400. N. What is the direction and magnitude of

the acceleration of the elevator?

57) A tightrope walker with a mass of 60.0 kg stands at the center of a rope which was initially strung horizontally

between two poles. His weight causes the rope to sag symmetrically, making an angle of 4.80° with the

horizontal. What is the tension in the rope?

58) A 10.0 kg picture is held in place by two wires, one hanging at 50.0° to the left of the vertical and the other is

horizontal. What is the tension in the wires?

Figure 5-27

59) A skier speeds down a trail, Figure 5-27. The surface is frictionless and inclined at an angle of 22.0° with the

horizontal. Find the acceleration of the skier.

60) A 2500 kg car accelerates from 0 to 21m/s in 5.2s. What is the friction force with the road, neglecting air

resistance?

Figure 6-1

61) In Figure 6-1, the block of mass 43.6 kg is at rest on an inclined plane that makes an angle of 25.1° with the

horizontal. What is the force of static friction?

62) Bobby (61kg) and Wayne (98kg) get in a tussle on the ice in a hockey game. If Bobby pushes Wayne with a force

of 77N what is the acceleration of each backwards? Neglect friction.

63) A tired mom puts a 0.200 kg latte on the roof of her car and forgets it. The coefficient of static friction between

the cup and the roof is 0.400. What is the maximum acceleration that the car can have if the cup is to stay in

place?

64) A horse pulls a 555 kg sleigh across a level snow covered field at constant speed. The coefficient of friction, µ,

is 0.15 between the sleigh and the snow. What is the force exerted on the horse by the sleigh?

Figure 6-11

65) Two masses are connected by a string which goes over an ideal pulley as shown in Figure 6-11. Block A has a

mass of 3.0 kg and can slide along a frictionless plane inclined 30° to the horizontal. What is the mass of block

B if the system is in equilibrium?Figure 6-12

66) Refer to Figure 6-12. Block A has a mass of 3.00 kg and rests on a frictionless table and is connected to block

B, which has a mass of 2.00 kg, after passing over an ideal pulley, as shown. Block B is released from rest.

What is the acceleration of the system?

Figure 6-10

67) A 3.00-kg mass (M1

) and a 5.00-kg mass (M2

) hang vertically at the ends of a rope that goes over an ideal pulley

(Figure 6-10). If the masses are released, what is the resulting acceleration of the system?

Answers:

1. The displacement is zero, the distance is quite large.

2. less than 64.3 km/h

3. average velocity

4. instantaneous velocity

5. instantaneous acceleration

6. vav

= ∆d/∆t

7. a = ∆v/∆t

8. The car is decelerating, and its acceleration is negative

and points West (‐x direction)

9. Displacement

10. its velocity is zero and its acceleration is straight down .

11. Its velocity points straight upward and its acceleration

points straight downward

12. 10.5 km

13. 0.67 m/s

14. 3 s

15. 18 m

16. a) 2 m/s

2

b) 0 m/s

2

17. 93.0 m/s

18. 14.5 m/s

19. 1.43 s

20. 5.8 m

21. 26 m

22. 0.25 s

23. 110 m/s

2

24. mass, time, speed, distance

25. displacement, velocity, acceleration, force, weight

26. 26.8 m

27. Its velocity is perpendicular to the acceleration

28. it will be directly over the bomb

29. 20 m/s horizontal

30. Vertical velocity is decreasing at 9.81 m/s

2

, Horizontal

velocity remains constant, Acceleration is 9.81m/s

2

down.

31. 0 m/s

32. 2.0 s

33. 1.4 seconds

34. 192m

35. 210 m

36. 35 m

37. 10.0 m

38. (a) 2.70 m/s (b) ‐20.6 m/s (c) 20.8m/s, 82.5°

39. move with constant velocity

40. (a) The net force on the object is zero

(b) they are balanced

41. the force of air resistance is equal and in opposite in

direction to the weight of the parachutist

42. 6000 N, they are a third law force pair

43. equal to its weight, 2.9 N

44. The elevator continues to descend with constant speed

45. equal to your true weight, mg

46. 520N

47. decreases

48. The two objects reach the bottom of the incline at the

same time

49. 1.5 x 10

‐13

N

50. 6.10 m/s

2

, 0.622

51. 94 N

52. 0.188 m/s

2

53. 396 N

54. 440 N, 367 N less

55. 312 N

56. 1.30 m/s

2

57. 3520 N

58. 153 N in angled wire, 117 N in horizontal wire

59. 3.67m/s

2

60. 10,000 N

61. 181 N

62. Bobby 1.3 m/s

2

, Wayne 0.79 m/s

2

63. 3.92 m/s

2

64. 820N

65. 1.5 kg

66. 3.92 m/s

2

67. 2.45 m/s

2

### Physics 101 Final Practice Exam

Practice FINAL EXAM

Physics 101

To get a full credit show the all calculations steps in the spaces provided. All work must be shown in order to receive FULL credit.

1) A car is traveling with a constant speed when the driver suddenly applies the brakes, giving the car a deceleration of 3.50 m/s2. If the car comes to a stop in a distance of 30.0 m, what was the car's original speed?

A) 10.2 m/s

B) 14.5 m/s

C) 105 m/s

D) 210 m/s

Answer: B

2) Two athletes jump straight up. John has twice the initial speed of Harry. Compared to Harry, John stays in the air

A) 1.41 times as long.

B) twice as long.

C) three times as long.

D) four times as long.

Answer: B

3) An astronaut stands by the rim of a crater on the moon, where the acceleration of gravity is 1.62 m/s2. To determine the depth of the crater, she drops a rock and measures the time it takes for it to hit the bottom. If the depth of the crater is 120 m, how long does it take for the rock to fall?

A) 3.04 s

B) 12.2 s

C) 29.3 s

D) 32.1 s

Answer: B

4) A car traveling with velocity v is decelerated by a constant acceleration of magnitude a. It travels a distance d before coming to rest. If its initial velocity were doubled, the distance required to stop would

A) double as well.

B) decrease by a factor of two.

C) stay the same.

D) quadruple.

Answer: D

5) Figure above represents the position of a particle as it travels along the x-axis. What is the average speed

of the A particle between t = 2 s and t = 4 s?

A) 1.0 m/s

B) 1.3 m/s

C) 0.67 m/s

D) 0.50 m/s

Answer: A

6) Figure above represents the position of a particle as it travels along the x-axis. What is the average velocity of the

particle between t = 2 s and t = 4 s?

A) 2.0 m/s

B) 1.3 m/s

C) 1.7 m/s

D) 0 m/s

Answer: D

7) To determine the height of a bridge above the water, a person drops a stone and measures the time it takes for it

to hit the water. If the height of the bridge is 41 m, how long will it take for the stone to hit the water?

A) 2.3 s

B) 2.6 s

C) 2.9 s

D) 3.2 s

Answer: C

8) A vector A has components Ax > 0, and Ay > 0, the angle that this vector makes with the positive x-axis must be

in the range

A) 0° to 90°.

B) 90° to 180°.

C) 180° to 270°.

D) 270° to 360°.

Answer: A

9) A car moves from the point (3.0 m) xˆ + (5.0 m) yˆ to the point (8.0 m) xˆ - (7.0 m) yˆ in 2.0 s. What is the

direction of the average velocity of the car?

A) 67° from the x-axis

B) -67° from the x-axis

C) 33° from the x-axis

D) -33° from the x-axis

Answer: B

10) A boy kicks a football with an initial velocity of 28.0 m/s at an angle of 30.00 above the horizontal. What is the

highest elevation reached by the football in its trajectory?

A) 11.2 m

B) 10.0 m

C) 12.7 m

D) 9.40 m

Answer: B

11) A ball rolls over the edge of a table with a horizontal velocity v m/s. The height of the table is 1.6 m and the

horizontal range of the ball from the base of the table is 20 m. What is the magnitude and direction of the ball's

acceleration right before it touches the ground?

A) 4.9 m/s2 downward

B) 0 m/s2 downward

C) 9.6 m/s2 downward

D) 9.8 m/s2 downward

Answer: D

12) A bullet is fired from ground level with a speed of 150 m/s at an angle 30.00 above the horizontal at a location

where g = 10.0 m/s2. What is the horizontal component of its velocity after 4 seconds?

A) 150 m/s

B) 0 m/s

C) 130 m/s

D) 75.0 m/s

Answer: C

13) A student kicks a soccer ball in a high arc toward the opponent's goal. At the highest point in its trajectory:

A) both velocity and acceleration of the soccer ball are zero.

B) neither the ball's velocity nor its acceleration is zero.

C) the ball's acceleration is zero but not its velocity.

D) the ball's acceleration points upwards.

Answer: B

14) A 10.0-kg picture is held in place by two wires, one hanging at 35.0° to the left of the vertical and the other at 45.0° to the right of the vertical. What is the tension in the first wire?

A) 70.4 N

B) 50.8 N

C) 98.1 N

D) 69.4 N

Answer: A

15) A 30.0-kg object slides down a slope which is inclined 27.0° to the horizontal. What is the normal force on the object?

A) 171 N

B) 262 N

C) 387 N

D) 398 N

Answer: B

16) Refer to Figure above. Block A has a mass of 3.00 kg, block B has a mass of 5.00 kg and block C has a mass of 2.00 kg. The pulleys are ideal and there is no friction between block B and the table. What is the acceleration of the masses?

A) 0.981 m/s2

B) 1.86 m/s2

C) 2.94 m/s2

D) 4.20 m/s2

Answer: A

17) A 1000-kg car is moving at 30.0 m/s around a horizontal curve whose radius is 100 m. What is the magnitude of the frictional force required to keep the car from sliding?

A) 9000 N

B) 9810 N

C) 300 N

D) 3000 N

Answer: A

18) Pulling out of a dive, the pilot of an airplane guides his plane into a vertical circle. At the bottom of the dive, the speed of the airplane is 320 m/s. What is the smallest radius allowable for the vertical circle if the pilot's apparent weight is not to exceed 7.00 times his true weight?

A) 1740 m

B) 1490 m

C) 2240 m

D) 228 m

Answer: A

19) An object is under the influence of a force as represented by the force vs. position graph in Figure above. What is the work done as the object moves from 0 m to 4 m?

A) 20 J

B) 30 J

C) 0 J

D) 40 J

Answer: A

20) An object of mass m moving in a certain direction has a kinetic energy of 4.0 J. It hits a wall and comes back with half its original kinetic energy. If the speed of the object on return is 2.0 m/s, what is the mass of the object?

A) 2.8 kg

B) 3.8 kg

C) 1.0 kg

D) 4.0 kg

Answer: C

A roller coaster of mass 80.0 kg is moving with a speed of 20.0 m/s at position A as shown in Figure. The vertical height at position A above ground level is 200 m. Neglect friction and use g = 10.0 m/s2.

21) Refer to Figure above. What is the total energy of the roller coaster at point A?

A) 16.0 × 103 J

B) 20.2 × 103 J

C) 16.0 × 104 J

D) 17.6 × 104 J

Answer: D

22) Refer to Figure above. What is the total energy of the roller coaster at point B?

A) 16.4 × 103 J

B) 20.2 × 103 J

C) 17.6 × 104 J

D) 16.4 × 104 J

Answer: C

23) A rocket is fired in a gravity-free environment in deep space. The rocket has an initial mass of 8000 kg and ejects gas with a velocity of 2000 m/s. How much gas must be ejected in the first second to give the rocket an acceleration of 30.0 m/s?

A) 120 kg

B) 7.50 kg

C) 15.0 kg

D) 150 kg

Answer: A

24) Earth's radius is 6.38 × 106 m, and it completes one revolution every day. What is the tangential speed of a person standing on the equator?

A) 232 m/s

B) 148 m/s

C) 464 m/s

D) 73.8 m/s

Answer: C

25) Neptune has a radius of 2.48 × 107 m and an escape velocity of 23,300 m/s. What is the mass of Neptune? G =

6.67 × 10-11 N•m2/kg2.

A) 1.01 × 1026 kg

B) 2.02 × 1026 kg

C) 3.03 × 1026 kg

D) 4.04 × 1026 kg

Answer: A

26) A car moving at 10.0 m/s encounters a bump that has a circular cross-section with a radius of 30.0 m. What is

the normal force exerted by the seat of the car on a 60.0-kg passenger when the car is at the top of the bump?

A) 200 N

B) 389 N

C) 789 N

D) 589 N

Answer: B

27) A 2-kg ball is moving with a constant speed of 5 m/s in a horizontal circle whose radius is 50 cm. What is the

acceleration of the ball?

A) 0 m/s2

B) 10 m/s2

C) 20 m/s2

D) 50 m/s2

Answer: D

28) A 15.0-kg child is sitting on a playground teeter-totter, 1.50 m from the pivot. What force, applied 0.300 m on

the other side of the pivot, is needed to make the child lift off the ground?

A) 75.0 N

B) 736 N

C) 44.1 N

D) 66.2 N

Answer: B

29) A figure skater is spinning slowly with arms outstretched. She brings her arms in close to her body and her

moment of inertia decreases by 1/2. By what factor does her rotational kinetic energy change?

A) 2

B) 4

C) 2

D) It doesn't change.

Answer: A

30) A fan is turned off, and its angular speed decreases from 10.0 rad/s to 6.3 rad/s in 5.0 s. What is the magnitude

of the angular acceleration of the fan?

A) 0.74 rad/s2

B) 0.37 rad/s2

C) 11.6 rad/s2

D) 1.16 rad/s2

Answer: A

## Tuesday, November 27, 2012

### Chapter 7 Rotational Motion Law of Gravity Quick Quizzes

1. (c). For a rotation of more than 180°,
the angular displacement must be larger than

*p*= 3.14 rad. The angular displacements in the three choices are (a) 6 rad - 3 rad = 3 rad, (b) 1 rad -(-1) rad = 2 rad, (c) 5 rad -1 rad = 4 rad.
2. (b). Because all angular displacements occurred in the same time
interval, the displacement with the lowest value will be associated with the
lowest average angular speed.

3. (b).
From

it is seen that the case with the smallest angular displacement involves the highest angular acceleration.

it is seen that the case with the smallest angular displacement involves the highest angular acceleration.

4. (b).
All points in a rotating rigid body have the same angular speed.

5. (a). Andrea and Chuck have the same
angular speed, but Andrea moves in a circle with twice the radius of the circle
followed by Chuck. Thus, from , it is seen that Andrea’s tangential speed is twice Chuck’s.

6.

**1. (e). Since the tangential speed is constant, the tangential acceleration is zero.**
2. (a). The centripetal acceleration, , is inversely proportional to the radius when the tangential
speed is constant.

3. (b). The angular speed, , is inversely proportional to the radius when the tangential
speed is constant.

7. (c). Both the velocity and acceleration
are changing in direction, so neither of these vector quantities is constant.

8.

**(b) and (c). According to Newton’s law of universal gravitation, the force between the ball and the Earth depends on the product of their masses, so both forces, that of the ball on the Earth, and that of the Earth on the ball, are equal in magnitude. This follows also, of course, from Newton’s third law. The ball has large motion compared to the Earth because according to Newton’s second law, the force gives a much greater acceleration to the small mass of the ball.**
9. (e). From

*F = G Mm/r*, the gravitational force is inversely proportional to the square of the radius of the orbit.^{2}
10.

**(d). The semi-major axis of the asteroid’s orbit is 4 times the size of Earth’s orbit. Thus, Kepler’s third law (***T*^{2}/*r*^{3}= constant) indicates that its orbital period is 8 times that of Earth.### Physics 101 Quiz Momentum, Kinematics, Collisions,

1

Momentum

____ 1. A ball with original momentum +4.0 kgm/s hits a wall and bounces straight back without losing any kinetic

energy. The change in momentum of the ball is:

a. 0. c. 8.0 kgm/s.

b. 4.0 kgm/s. d. 8.0 kgm/s.

____ 2. A 75-kg swimmer dives horizontally off a 500-kg raft. The diver's speed immediately after leaving the raft is

4.0 m/s. A micro-sensor system attached to the edge of the raft measures the time interval during which the

diver applies an impulse to the raft just prior to leaving the raft surface. If the time interval is read as 0.20 s,

what is the magnitude of the average horizontal force by diver on the raft?

a. 900 N c. 525 N

b. 450 N d. 1 500 N

____ 3. A 0.12-kg ball is moving at 6 m/s when it is hit by a bat, causing it to reverse direction and have a speed of 14

m/s. What is the change in the magnitude of the momentum of the ball?

a. 0.39 kgm/s c. 1.3 kgm/s

b. 0.42 kgm/s d. 2.4 kgm/s

____ 4. Alex throws a 0.15-kg rubber ball down onto the floor. The ball's speed just before impact is 6.5 m/s, and just

after is 3.5 m/s. What is the change in the magnitude of the ball's momentum?

a. 0.09 kgm/s c. 4.3 kgm/s

b. 1.5 kgm/s d. 126 kgm/s

____ 5. Alex throws a 0.15-kg rubber ball down onto the floor. The ball's speed just before impact is 6.5 m/s, and just

after is 3.5 m/s. If the ball is in contact with the floor for 0.025 s, what is the magnitude of the average force

applied by the floor on the ball?

a. 60 N c. 3.0 N

b. 133 N d. 3.5 N

____ 6. A crane drops a 0.30 kg steel ball onto a steel plate. The ball's speeds just before impact and after are 4.5 m/s

and 4.2 m/s, respectively. If the ball is in contact with the plate for 0.030 s, what is the magnitude of the

average force that the ball exerts on the plate during impact?

a. 87 N c. 3.0 N

b. 133 N d. 3.5 N

____ 7. Jerome pitches a baseball of mass 0.20 kg. The ball arrives at home plate with a speed of 40 m/s and is batted

straight back to Jerome with a return speed of 60 m/s. What is the magnitude of change in the ball's

momentum?

a. 4.0 kgm/s c. 18 kgm/s

b. 8.0 kgm/s d. 20 kgm/s

____ 8. Lonnie pitches a baseball of mass 0.20 kg. The ball arrives at home plate with a speed of 40 m/s and is batted

straight back to Lonnie with a return speed of 60 m/s. If the bat is in contact with the ball for 0.050 s, what is

the impulse experienced by the ball?

a. 360 Ns c. 400 Ns

b. 20 Ns d. 9.0 Ns2

____ 9. A car wash nozzle directs a steady stream of water at 1.5 kg/s, with a speed of 30 m/s, against a car window.

What force does the water exert on the glass? Assume the water does not splash back.

a. 11 N c. 110 N

b. 45 N d. 440 N

____ 10. A 75-kg swimmer dives horizontally off a 500-kg raft. If the diver's speed immediately after leaving the raft is

4 m/s, what is the corresponding raft speed?

a. 0.2 m/s c. 0.6 m/s

b. 0.5 m/s d. 4.0 m/s

____ 11. A cannon of mass 1 500 kg fires a 10-kg shell with a velocity of 200 m/s at an angle of 45 above the

horizontal. Find the recoil velocity of the cannon across the level ground.

a. 1.33 m/s c. 2.41 m/s

b. 0.94 m/s d. 1.94 m/s

____ 12. A machine gun is attached to a railroad flatcar that rolls with negligible friction. If the railroad car has a mass

of 6.25 10

4

kg, how many bullets of mass 25 g would have to be fired at 250 m/s off the back to give the

railroad car a forward velocity of 0.5 m/s?

a. 400 c. 3 000

b. 2 000 d. 5 000

____ 13. Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite

away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?

a. 4.0 m/s c. 8.5 m/s

b. 5.3 m/s d. 9.0 m/s

____ 14. A miniature spring-loaded, radio-controlled gun is mounted on an air puck. The gun's bullet has a mass of

5.00 g, and the gun and puck have a combined mass of 120 g. With the system initially at rest, the radio

controlled trigger releases the bullet causing the puck and empty gun to move with a speed of 0.500 m/s.

What is the bullet's speed?

a. 4.80 m/s c. 48.0 m/s

b. 11.5 m/s d. 12.0 m/s

____ 15. A uranium nucleus (mass 238 units) at rest decays into a helium nucleus (mass 4.0 units) and a thorium

nucleus (mass 234 units). If the speed of the helium nucleus is 6.0 10

5

m/s, what is the speed of the thorium

nucleus?

a. 1.0 10

4

m/s c. 3.6 10

4

m/s

b. 3.0 10

4

m/s d. 4.1 10

4

m/s

____ 16. A 20-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s. If

the block had been originally at rest and is free to move, what is its resulting speed?

a. 9 m/s c. 90 m/s

b. 18 m/s d. 900 m/s

____ 17. A 20-g bullet moving at 1 000 m/s is fired through a one-kg block of wood emerging at a speed of 100 m/s.

What is the kinetic energy of the block that results from the collision if the block had not been moving prior

to the collision and was free to move?

a. 10 kJ c. 0.16 kJ

b. 9.8 kJ d. 0.018 kJ3

____ 18. A billiard ball is moving in the x-direction at 30.0 cm/s and strikes another billiard ball moving in the

y-direction at 40.0 cm/s. As a result of the collision, the first ball moves at 50.0 cm/s, and the second ball

stops. In what final direction does the first ball move?

a. in the x-direction c. at an angle of 45.0 ccw from the

x-direction

b. at an angle of 53.1 ccw from the

x-direction

d. Such a collision cannot happen.

____ 19. During a snowball fight two balls with masses of 0.4 and 0.6 kg, respectively, are thrown in such a manner

that they meet head-on and combine to form a single mass. The magnitude of initial velocity for each is 15

m/s. What is the speed of the 1.0-kg mass immediately after collision?

a. zero c. 6 m/s

b. 3 m/s d. 9 m/s

____ 20. A 2 500-kg truck moving at 10.00 m/s strikes a car waiting at a traffic light, hooking bumpers. The two

continue to move together at 7.00 m/s. What was the mass of the struck car?

a. 1 730 kg c. 1 200 kg

b. 1 550 kg d. 1 070 kg

____ 21. A 0.10-kg object moving initially with a velocity of +0.20 m/s makes an elastic head-on collision with a

0.15-kg object initially at rest. What percentage of the original kinetic energy is retained by the 0.10-kg

object?

a. 4% c. 50%

b. 4% d. 96%

____ 22. Two billiard balls have velocities of 2.0 m/s and 1.0 m/s when they meet in an elastic head-on collision.

What is the final velocity of the first ball after collision?

a. 2.0 m/s c. 0.5 m/s

b. 1.0 m/s d. +1.0 m/s

____ 23. Two objects, one less massive than the other, collide elastically and bounce back after the collision. If the two

originally had velocities that were equal in size but opposite in direction, then which one will be moving

faster after the collision?

a. The less massive one. c. The speeds will be the same after the

collision.

b. The more massive one. d. There is no way to be sure without the

actual masses.

____ 24. A 7.0-kg bowling ball strikes a 2.0-kg pin. The pin flies forward with a velocity of 6.0 m/s; the ball continues

forward at 4.0 m/s. What was the original velocity of the ball?

a. 4.0 m/s c. 6.6 m/s

b. 5.7 m/s d. 3.3 m/s

____ 25. Two skaters, both of mass 75 kg, are on skates on a frictionless ice pond. One skater throws a 0.3-kg ball at 5

m/s to his friend, who catches it and throws it back at 5 m/s. When the first skater has caught the returned ball,

what is the velocity of each of the two skaters?

a. 0.02 m/s, moving apart c. 0.02 m/s, moving towards each other

b. 0.04 m/s, moving apart d. 0.04 m/s, moving towards each other4

____ 26. A 90-kg halfback running north with a speed of 10 m/s is tackled by a 120-kg opponent running south at 4

m/s. The collision is perfectly inelastic. Compute the velocity of the two players just after the tackle.

a. 3 m/s south c. 2 m/s north

b. 2 m/s south d. 3 m/s north

____ 27. Popeye, of mass 70 kg, has just downed a can of spinach. He accelerates quickly and stops Bluto, of mass 700

kg (Bluto is very dense), who is charging in at 10 m/s. What was Popeye's speed?

a. 10 m/s c. 50 m/s

b. 31 m/s d. 100 m/s

____ 28. Two identical 7-kg bowling balls roll toward each other. The one on the left is moving at +4 m/s while the

one on the right is moving at 4 m/s. What is the velocity of each ball after they collide elastically?

a. Neither is moving. c. +4 m/s, 4 m/s

b. 4 m/s, +4 m/s d. 14 m/s, 14 m/s

____ 29. A 5-kg object is moving to the right at 4 m/s and collides with a 4-kg object moving to the left at 5 m/s. The

objects collide and stick together. After the collision, the combined object:

a. has the same kinetic energy that the

system had before the collision.

c. has no kinetic energy.

b. has more kinetic energy than the system

had before the collision.

d. has less momentum than the system had

before the collision.

____ 30. A model car is propelled by a cylinder of carbon dioxide gas. The cylinder emits gas at a rate of 4.5 g/s with

an exit speed of 80.0 m/s. The car has a mass of 400 g, including the CO2 cylinder. Starting from rest, what is

the car's initial acceleration?

a. 0.90 m/s

2

c. 9.0 m/s

2

b. 4.5 m/s

2

d. 36 m/s

2

____ 31. A 1 000-kg experimental rocket sled on level frictionless rails is loaded with 50 kg of propellant. It exhausts

the propellant in a 20-s "burn." If the rocket, initially at rest, moves at 150 m/s after the burn, what impulse is

experienced by the rocket sled?

a. 1.1 10

5

kgm/s c. 1.5 10

5

kgm/s

b. 1.6 10

5

kgm/s d. 1.9 10

5

kgm/s

____ 32. A 1 000-kg experimental rocket sled at rest on level frictionless rails is loaded with 50 kg of propellant. It

exhausts the propellant in a 20-s "burn." The rocket moves at 150 m/s after the burn. What average force is

experienced by the rocket during the burn?

a. 0.95 10

4

N c. 0.60 10

4

N

b. 0.75 10

4

N d. 0.35 10

4

N

____ 33. A helicopter stays aloft by pushing large quantities of air downward every second. What mass of air must be

pushed downward at 40.0 m/s every second to keep a 1 000-kg helicopter aloft?

a. 120 kg c. 360 kg

b. 245 kg d. 490 kg

____ 34. At liftoff, the engines of the Saturn V rocket consumed 13 000 kg/s of fuel and exhausted the combustion

products at 2 900 m/s. What was the total upward force (thrust) provided by the engines?

a. 3.77 10

7

N c. 1.47 10

8

N

b. 7.54 10

7

N d. 2.95 10

8

N5

____ 35. A rocket of total mass M and with burnout mass 0.20 M attains a speed of 3 200 m/s after starting from rest in

deep space. What is the exhaust velocity of the rocket?

a. 1 000 m/s c. 3 000 m/s

b. 2 000 m/s d. 4 000 m/s

____ 36. Two masses collide and stick together. Before the collision one of the masses was at rest. Is there a situation

in which the kinetic energy is conserved in such a collision?

a. Yes, if the less massive particle is the one

initially at rest.

c. Yes, if the two particles have the same

mass.

b. Yes, if the more massive particle is the

one initially at rest.

d. No, kinetic energy is always lost is such a

collision.

____ 37. In an automobile collision, how does an airbag lessen the blow to the passenger? Assume as a result of the

collision, the passenger stops.

a. The air bag decreases the momentum

change of the passenger in the collision.

c. The stopping impulse is the same for

either the hard objects or the airbag.

Unlike the windshield or dashboard, the

air bag gives some increasing the time for

the slowing process and thus decreasing

the average force on the passenger.

b. During the collision, the force from the

air bag is greater than would be the force

from the windshield or dashboard so the

passenger cannot hit the hard objects.

d. The airbag is there to insure the seatbelt

holds.

____ 38. Two masses m1 and m2, with m1 < m2, have momenta with equal magnitudes. How do their kinetic energies

compare?

a. KE1 < KE2 c. KE1 > KE2

b. KE1 = KE2 d. More information is needed.ID: A

1

Momentum

Answer Section

MULTIPLE CHOICE

1. D

2. D

3. D

4. B

5. A

6. A

7. D

8. B

9. B

10. C

11. B

12. D

13. B

14. D

15. A

16. B

17. C

18. B

19. B

20. D

21. A

22. B

23. A

24. B

25. B

26. C

27. D

28. B

29. C

30. A

31. C

32. B

33. B

34. A

35. B

36. D

37. C

38. C

### Multiple Choice Physics 101 Quiz

**MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.**

1) The work done by the centripetal force on an object with a mass of 1 kg moving with a constant velocity of 4 m/s into a circular path of radius 0.6 m for one full cycle is

A) 100.7 J B) 3.8 J C) 0 J D) 80 J

Answer: C

2) A truck has four times the mass of a car and is moving with twice the speed of the car. If K

_{t}and K_{c}refer to the kinetic energies of truck and car respectively, it is correct to say that
A) K

_{t}= 16K_{c}B) K_{t}= 4K_{c}C) K_{t}= K_{c}D) K_{t}= 1/2 K_{c}
Answer: A

**Figure 7-4**

3) An object is under the influence of a force as represented by the force vs. position graph in Figure 7-4. What is the work done as the object moves from 6 m to 12 m?

A) 20 J B) 30 J C) 0 J D) 40 J

Answer: B

4) A car accelerates from rest to a speed of 20.0 m/s in 6.00 seconds. If the car weighs 16,000 N, what average power must the motor produce to cause this acceleration?

A) 128 kW B) 15.0 kW C) 54 .4 kW D) 219 kW

Answer: C

**A mass of 1.0 kg is pushed against a spring with a spring constant of 25 N/m. As a result, the spring is compressed by 20 cm. The mass is then released.**

5) What is the amount of work required to compress the spring?

A) 5.0 J

B) 0.20 J

C) 0.50 J

D) 10 J

Answer: C

6) An object of mass

*m*is held at a vertical height*h*from ground level. It is then released and falls under the influence of gravity. Which of the following statements is true in this situation? (Neglect air resistance.)
A) The total energy of the object is decreasing.

B) The kinetic energy of the object is decreasing.

C) The total energy of the object is increasing.

D) The potential energy of the object is decreasing and the kinetic energy is increasing.

Answer: D

**Figure 8-7**

An object with a mass of 10.0 kg is at rest at the top of a frictionless inclined plane of height 8.00 m and an angle of inclination 30.0e with the horizontal. The object is released from this position and it stops at a distance

*d*from the bottom of the inclined plane along a horizontal surface, as shown in Figure 8-7. The coefficient of kinetic friction for the horizontal surface is 0.400 and*g*= 10.0 m/ s to power of (exponent).
7) Refer to Figure 8-7. What is the kinetic energy of the object at the bottom of the inclined plane?

A) 400 J

B) 500 J

C) 700 J

D) 800 J

Answer: D

**Figure 8-10**

**2-kg mass is moving along the**

*x*axis. The potential energy curve as a function of position is shown in Figure 8-10. The system is conservative. There is no friction.
8) Refer to Figure 8-10. If the object is at rest at the origin, what will be its speed at 9.0 m along the +

*x*-axis?
A) 1.5 m/s

B) 2.5 m/s

C) 3.5 m/s

D) 4.5 m/s

Answer: C

9) A golf club exerts an average force of 1000 N on a 0.045-kg golf ball which is initially at rest. The club is in contact with the ball for 1.8 ms. What is the speed of the golf ball as it leaves the tee?

A) 35 m/s

B) 40 m/s

C) 45 m/s

D) 50 m/s

Answer: B

10) In a collision between two unequal masses, how does the impulse imparted to the smaller mass by the larger mass compare with the impulse imparted to the larger mass by the smaller one?

A) It is larger.

B) It is smaller.

C) They are equal.

D) The answer depends on how fast they are moving.

Answer: C

11) An elastic collision of two objects is characterized by the following.

A) Total momentum of the system is conserved.

B) Total kinetic energy of the system remains constant.

C) Both A and B are true.

D) Neither A nor B are true.

Answer: C

12) A uniform piece of wire, 20 cm long, is bent in a right angle in the center to give it an L-shape. How far from the bend is the center of mass of the bent wire?

A) 2.5 cm

B) 3.5 cm

C) 5.0 cm

D) 7.1 cm

Answer: B

13) How long does it take a wheel that is rotating at 33.3 rpm to speed up to 78.0 rpm if it has an angular acceleration of 2.15 rad/ s to power of (exponent)?

A) 20.8 s

B) 10.4 s

C) 2.18 s

D) 5.20 s

Answer: C

14) A Ferris wheel with a radius of 12.0 m rotates at a constant rate, completing one revolution in 30.0 s. What is the apparent weight of a 60.0-kg passenger when she is at the top of the wheel?

A) 589 N

B) 557 N

C) 615 N

D) 325 N

Answer: B

15) A dumbbell-shaped object is composed by two equal masses,

*m*, connected by a rod of negligible mass and length*r.*If*I*_{1}is the moment of inertia of this object with respect to an axis passing through the center of the rod and perpendicular to it and*I*_{2}is the moment of inertia with respect to an axis passing through one of the masses we can say that
A)

*I*_{1}*= I*_{2}
B)

*I*_{1}*> I*_{2}
C)

*I*_{1}*< I*_{2}
D) There is no way to compare

*I*_{1}*and**I*_{2}*.*
Answer: C

16) A solid disk, a hoop, and a solid sphere are released at the same time at the top of an inclined plane. They all roll without slipping. In what order do they reach the bottom?

A) disk, hoop, sphere

B) sphere, disk, hoop

C) hoop, sphere, disk

D) hoop, disk, sphere

Answer: B

17) The rotating systems shown in the figure differ only in that the two identical movable masses are positioned a distance

*r*from the axis of rotation (left), or a distance*r*/2 from the axis of rotation (right). If you release the hanging blocks simultaneously from rest,
A) the block at left lands first.

B) the block at right lands first.

C) both blocks land at the same time.

D) it is impossible to tell which block reaches the bottom first.

Answer: B

18) A 3.00-m-long ladder, weighing 200 N, rests against a smooth vertical wall with its base on a horizontal rough floor, a distance of 1.20 m away from the wall. If the center of mass of the ladder is 1.40 m from its base, what frictional force must the floor exert on the base of the ladder in order for the ladder to be in static equilibrium?

A) 93.3 N

B) 130 N

C) 40.7 N

D) 102 N

Answer: C

19) A puck moves on a horizontal air table. It is attached to a string that passes through a hole in the center of the table. As the puck rotates about the hole, the string is pulled downward very slowly and shortens the radius of rotation, so the puck gradually spirals in towards the center. By what factor will the puck's angular speed have changed when the string's length has decreased by 1/2?

A) 2

B) 4

C) sqrt(2)

D) 1

Answer: B

**Figure 11-6**

20) The L-shaped object shown in Figure 11-6 consists of the masses connected by light rods. How much work must be done to accelerate the object from rest to an angular speed of 3.25 rad/s about the

*y*-axis?
A) 374 J

B) 173 J

C) 42.2 J

D) 27.4 J

Answer: B

### Physics 101 Practice Quiz 8

Practice Quiz 8

1) A 0.140-kg baseball is dropped from rest from a height of 1.8 m above the ground. It rebounds to a

height of 1.4 m. What change in the ball's momentum occurs when the ball hits the ground?

A) 0.117 kg•m/s upwards

B) 0.117 kg•m/s downwards

C) 1.57 kg•m/s upwards

D) 0.350 kg•m/s upwards

Answer: C

2) Two different masses have equal, non-zero kinetic energies. The momentum of the smaller mass is

A) smaller than the momentum of the larger mass.

B) larger than momentum of the larger mass.

C) equal to the momentum of the larger mass.

D) There is not enough information to answer the question.

Answer: A

3) In a collision between two unequal masses, how does the impulse imparted to the smaller mass by the

larger mass compare with the impulse imparted to the larger mass by the smaller one?

A) It is larger.

B) It is smaller.

C) They are equal.

D) The answer depends on how fast they are moving.

Answer: C

4) Two ice skaters push off against one another starting from a stationary position. The 45-kg skater

acquires a speed of 0.375 m/s. What speed does the 60-kg skater acquire?

A) 0.500 m/s

B) 0.281 m/s

C) 0.375 m/s

D) 0 m/s

Answer: B

5) An artillery shell explodes in midair and breaks up into many fragments. Which of the following

statements are true regarding conditions immediately before and immediately after the explosion:

I. The total momentum of the fragments is equal to the original momentum of the shell.

II. The total kinetic energy of the fragments is equal to the original kinetic energy of the shell.

A) Statement I only

B) Statement II only

C) Both Statement I and Statement II

D) Neither statement is true.

Answer: A

6) A 900-kg car traveling east at 15.0 m/s collides with a 750-kg car traveling north at 20.0 m/s. The cars

stick together. In what direction does the wreckage move just after the collision?

A) 36.9e N of E

B) 42.0e N of E

C) 53.1e N of E

D) 48.0e N of E

Answer: D

7) A 750-g mass traveling at 8.0 m/s undergoes a head-on elastic collision with a 50-g mass traveling

toward it also at 8.0 m/s. What is the speed of the 50-g mass after the collision?

A) 15 m/s

B) 4.0 m/s

C) 22 m/s D) 0 m/s

Answer: C

8) A 340-g air track cart traveling at 1.25 m/s collides elastically with a 300-g cart traveling in the opposite

direction at 1.33 m/s. What is the speed of the 300-g cart after the collision?

A) 2.80 m/s

B) 0.0693 m/s

C) 1.41 m/s

D) 1.29 m/s

Answer: C

9) A 60.0-kg man stands at one end of a 20.0-kg uniform 10.0-m long board. How far from the man is the

center of mass of the man-board system?

A) 1.25 m

B) 2.50 m

C) 5.00 m

D) 7.50 m

Answer: A

10) Three masses are located in the x-y plane as follows: a mass of 6 kg is located at (0 m, 0 m), a mass of

4 kg is located at (3 m, 0 m), and a mass of 2 kg is located at (0 m, 3 m). Where is the center of mass of the

system?

A) (1 m, 2 m) B) (2 m, 1 m) C) (1 m, 1 m) D) (1 m, 0.5 m)

Answer: D

11) An elastic collision of two objects is characterized by the following.

A) Total momentum of the system is conserved.

B) Total kinetic energy of the system remains constant.

C) Both A and B are true.

D) Neither A nor B are true.

Answer: C

12) A tennis ball undergoes an elastic collision when it hits the ground and bounces up. It is given that the

speed of the ball just before it hits the ground is -v0 and immediately after rebounding it is +v0. Which of

the statements below is true?

A) The momentum of the ball changes but the momentum of Earth does not.

B) The momentum of the ball changes and the momentum of Earth also changes.

C) The momentum of the ball does not change but the momentum of Earth changes.

D) Neither the momentum of the ball nor the momentum of Earth changes.

Answer: B

13) You are standing at a bus stop holding an umbrella on a rainy day. While you wait for the bus the rain

shower turns into hail. Compared to the rain, the number of hail "drops" hitting the umbrella per second,

the mass of the "drops", and their speed all remain the same. The force you must exert to hold the umbrella

in the hail is

A) less than the force required in the rain.

B) the same as the force required in the rain.

C) more than the force required in the rain.

D) impossible to compare with the force required in the rain.

Answer: C

14) A 750-g mass traveling at 8.0 m/s undergoes a head-on elastic collision with a 50-g mass traveling

toward it also at 8.0 m/s. What is the speed of the 50-g mass after the collision?

A) 15 m/s B) 4.0 m/s C) 22 m/s D) 0 m/s

Answer: C

### Practice Quiz 2 on Chapter 6 Collision Momentum Energy Potential, Kinetic

1. Alex throws a 0.15-kg rubber ball down onto the floor. The ball's speed just before impact is 6.5 m/s, and just after is 3.5 m/s. What is the change in the magnitude of the ball's momentum?

a. 0.09 kg m/s

b. 1.5 kg m/s

c. 4.3 kg m/s

d. 126 kg m/s

2. A ball with original momentum +4.0 kg m/s hits a wall and bounces straight back without losing any kinetic energy. The change in the momentum of the ball is:

a. 0

b. -4.0 kg m/s

c. 8.0 kg m/s

d. -8.0 kg m/s

3. Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?

a. 4.0 m/s

b. 5.3 m/s

c. 8.5 m/s

d. 9.0 m/s

4. If the momentum of an object is tripled, its kinetic energy will change by what factor?

a. zero

b. one-third

c. three

d. nine

5. A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually doesn't break. This is because for the egg dropped on the grass:

a. the change in momentum is greater.

b. the change in momentum is less

c. the time interval for stopping is greater

d. the time interval for stopping is less

6. An elastic collision of two objects is characterized by the following:

a. Total momentum of the system is conserved

b. Total kinetic energy of the system remains constant

c. Both A and B are true.

d. Neither A nor B are true.

7. Two ice skaters push off against one another starting from a stationary position. The 45-kg skater acquires a speed of 0.375 m/s. What speed does the 60-kg skater acquire?

a. 0.500 m/s

b. 0.281 m/s

c. 0.375 m/s

d. 0 m/s

a. 0.09 kg m/s

b. 1.5 kg m/s

c. 4.3 kg m/s

d. 126 kg m/s

2. A ball with original momentum +4.0 kg m/s hits a wall and bounces straight back without losing any kinetic energy. The change in the momentum of the ball is:

a. 0

b. -4.0 kg m/s

c. 8.0 kg m/s

d. -8.0 kg m/s

3. Ann the Astronaut weighs 60 kg. She is space walking outside the space shuttle and pushes a 350-kg satellite away from the shuttle at 0.90 m/s. What speed does this give Ann as she moves toward the shuttle?

a. 4.0 m/s

b. 5.3 m/s

c. 8.5 m/s

d. 9.0 m/s

4. If the momentum of an object is tripled, its kinetic energy will change by what factor?

a. zero

b. one-third

c. three

d. nine

5. A moderate force will break an egg. However, an egg dropped on the road usually breaks, while one dropped on the grass usually doesn't break. This is because for the egg dropped on the grass:

a. the change in momentum is greater.

b. the change in momentum is less

c. the time interval for stopping is greater

d. the time interval for stopping is less

6. An elastic collision of two objects is characterized by the following:

a. Total momentum of the system is conserved

b. Total kinetic energy of the system remains constant

c. Both A and B are true.

d. Neither A nor B are true.

7. Two ice skaters push off against one another starting from a stationary position. The 45-kg skater acquires a speed of 0.375 m/s. What speed does the 60-kg skater acquire?

a. 0.500 m/s

b. 0.281 m/s

c. 0.375 m/s

d. 0 m/s

### Sample Physics Test Solutions Centripetal Forces

Exam

Name___________________________________

TRUE/FALSE. Write 'T' if the statement is true and 'F' if the statement is false.

1) The kinetic energy of a skater increases when she moves her arms outward.

2) When a skater pulls his arms in, his angular velocity decreases

3) Mass is a measure of how difﬁcult it is to change the velocity of an object.

4) Force is a vector quantity.

5) When a ball is thrown upwards, it reaches its maximum height when the force pushing it up is equal to its

weight.

6) The acceleration of an object does not have to be in the same direction as the net force applied to it.

7) The mass of an object is ﬁxed, but its weight varies from location to location.

8) The force you exert on Earth is insigniﬁcant compared to the force Earth exerts on you.

9) A particle that has zero momentum must also have zero kinetic energy.

10) Internal forces cannot change the total momentum of a system.

11) In a one-dimensional elastic collision of two identical masses, the masses exchange velocities.

12) The center of mass of an object does not have to be located within the object.

13) Work is a vector quantity.

14) Work done by a force on an object can be a positive or a negative quantity.

15) The kinetic energy of an object of massm increases linearly as the velocity of the object increases.

16) Kinetic energy is a scalar quantity.

17) The work required to stretch a spring changes linearly with the amount of stretch.

18) The force acting on an object is said to be conservative if the work done by this force on the object is

independent of the path chosen.

19) The gravitational force is a conservative force.

20) Potential energy may be positive or negative.

121) Kinetic energy may be positive or negative.

22) The sum of the kinetic and potential energies of an object is conserved only when the object is under the

inﬂuence of conservative forces.

23) The positive direction for angular velocity is the clockwise direction.

24) When a rigid body rotates about a ﬁxed axis all the points in the body have the same angular speed.

25) Wave pulses in a slinky can only be transverse waves.

26) A wave pulse on a string whose end is ﬁxed is reﬂected without inversion.

27) Sound waves in air are transverse waves.

28) The coulomb, which is the unit of charge, is equivalent to the charge on a large number of electrons.

29) A good conductor of electricity is a bad conductor of heat.

30) If a conductor is placed in an electric ﬁeld under electrostatic conditions, the electric ﬁeld is excluded from

the inside of the conductor.

31) When a negatively charged rod is brought close to an electroscope, the positive charges in the electroscope

leaves move close to the negatively charged rod and the negative charges move into the leaves causing the

leaves to separate.

32) Conventional current is the ﬂow of positive charge from higher to lower potential.

33) Four unequal resistors connected in series have same current but different voltages.

34) In Young's double-slit experiment, light coming from each slit arrives in phase at the ﬁrst maximum on

either side of the central bright fringe.

MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question.

35) A 5 kg mass is moved a distance of 10 meters vertically in 20 seconds. What average power was required?

(Use g= 10 m/s

2)

A) 50 W B) 50 J C) 0 W D) 25 W

36) You drive 6.00 km at 50.0 km/h and then another 6.00 km at 90.0 km/h. Your average speed over the 12.0 km

drive will be

A) less than 70.0 km/h. B) equal to 70.0 km/h.

C) greater than 70.0 km/h. D) exactly 38.0 km/h.

37) At a given instant, the acceleration of a certain particle is zero. This means that

A) the velocity is increasing. B) the velocity is decreasing.

C) the velocity is constant. D) the velocity is not changing at that instant.

238) A car starts from rest and accelerates at 6.00 m/s

2

. How far does it travel in 3.00 s?

A) 18.0 m B) 36.0 m C) 54.0 m D) 27.0 m

39) An object is thrown upwards with a speed of 14 .0 m/s. How long does it take it to reach its maximum

height?

A) 1.22 s B) 4.15 s C) 3.14 s D) 1.43 s

40) From the edge of a roof top you toss a green ball upwards with initial velocityv 0 and a blue ball downwards

with the same initial velocity. When they reach the ground below,

A) the two balls will have the same speed.

B) the blue ball will be moving faster than the green ball.

C) the green ball will be moving faster than the blue ball.

D) None of the previous choices is correct.

41) A car is making a 12-mile trip. It travels the ﬁrst 6.0 miles at 30 miles per hour and the last 6.0 miles at 60

miles per hour. What is the car's average speed for the entire trip?

A) 50 mph B) 45 mph C) 40 mph D) 35 mph

42) An object is moving with constant velocity. Which of the following statements is true?

A) A constant force is being applied in the direction of motion.

B) There are no forces acting on the object.

C) The net force on the object is zero N.

D) There is no frictional force acting on the object.

43) A 55.0-kg box rests on a horizontal surface. The coefﬁcient of static friction between the box and the surface

is 0.300. A horizontal force of 156 N is applied to the box. Does the box move?

A) No B) Yes

44) When a parachutist jumps from an airplane, he eventually reaches a constant speed, called the terminal

velocity. This means that

A) the force of air resistance is equal to zero N.

B) the force of air resistance is equal to the weight of the parachutist.

C) the acceleration is equal tog.

D) the effect of gravity has died down.

45) A force of 120 N is applied to an object whose mass is 30 kg. The object's acceleration is

A) 3600 m/s

2

. B) 0.25 m/s

2

. C) 150 m/s

2

. D) 4.0 m/s

2

.

46) A net force of 125 N is applied to a certain object. As a result, the object accelerates with an acceleration of

24.0 m/s

2

. The mass of the object is

A) 144 kg. B) 0.200 kg. C) 2880 kg. D) 5.20 kg.

47) You apply the same force to two objects. Object 1 has massM and object 2 has mass 5M. The acceleration of

object 2 is

A) the same as that of object 1. B) ﬁve times that of object 1.

C) one-ﬁfth as that of object 1. D) has no relation to that of object 1.

348) A horse pulls a cart with force F . As a result of this force the cart accelerates with constant acceleration.

What is the magnitude of the force that the cart exerts on the horse?

A) Zero N B) Less than the magnitude of F

C) More than the magnitude of F D) Equal to the magnitude of F

49) A ball is thrown up into the air. Ignore air resistance. When it is rising and reaches half of its maximum

height, the net force acting on it is

A) zero N. B) less than its weight, but not zero N.

C) equal to its weight. D) greater than its weight.

50) A person has a mass of 45 kg. How much does she weigh?

A) 440 N B) 99 N C) 4.6 N D) 20 N

51) A 40.0-kg crate is being raised by means of a rope. Its upward acceleration is 2.00 m/s

2

. What is the force

exerted by the rope on the crate?

A) 312 N B) 472 N C) 392 N D) 552 N

52) A person is lowering a bucket into a well with a constant speed. The force exerted by the rope on the bucket

is

A) greater than the bucket's weight. B) zero N.

C) equal to the bucket's weight. D) less than the bucket's weight, but not zero N.

53) As a car drives with its tires rolling freely without any slippage, the type of friction acting between the tires

and the road is

A) static friction.

B) kinetic friction.

C) a combination of static and kinetic friction.

D) It is impossible to tell what type of friction acts in this situation.

54) You ride on an elevator that is moving with constant downward acceleration while standing on a bathroom

scale. The reading on the scale is

A) could be more or less than your true weight,mg, depending on the magnitude of the acceleration.

B) more than your true weight,mg.

C) equal to your true weight,mg.

D) less than your true weight,mg.

55) What does the word "normal" mean in the phrase "normal force"?

A) the total force exerted by a surface

B) the component of the force exerted by a surface perpendicular to the surface

C) the component of the force exerted by a surface parallel to the surface

D) the force that is usually exerted by a surface

56) A 30.0-kg object slides down a slope which is inclined 27.0° to the horizontal. What is the normal force on

the object?

A) 171 N B) 262 N C) 387 N D) 398 N

457) An object rests on an inclined surface. If the inclination of the surface is made steeper, what does the normal

force on the object do?

A) increase B) The normal force is zero N.

C) stays the same D) decrease

58) Two air track carts move along an air track towards each other. Cart A has a mass of 450 g and moves toward

the right with a speed of 0.850 m/s and air track cart B has a mass of 300 g and moves toward the left with a

speed of 1.12 m/s. What is the total momentum of the system?

A) 0.750 kg∙m/s toward the right B) 0.750 kg∙m/s toward the left

C) 0.719 kg∙m/s toward the right D) 0.047 kg∙m/s toward the right

59) A golf club exerts an average force of 1000 N on a 0.045-kg golf ball which is initially at rest. The club is in

contact with the ball for 1.8 ms. What is the speed of the golf ball as it leaves the tee?

A) 50 m/s B) 45 m/s C) 40 m/s D) 35 m/s

60) Identical forces act for the same length of time on two different masses. The change in momentum of the

smaller mass is

A) zero kg∙m/s.

B) smaller than the change in momentum of the larger mass, but not zero kg∙m/s.

C) equal to the change in momentum of the larger mass.

D) larger than the change in momentum of the larger mass.

61) Two different masses have equal, non-zero kinetic energies. The momentum of the smaller mass is

A) larger than momentum of the larger mass.

B) equal to the momentum of the larger mass.

C) smaller than the momentum of the larger mass.

D) There is not enough information to answer the question.

62) A 0.330-kg volleyball is dropped from rest. It takes it 1.30 s to reach the ground. What is the magnitude of its

momentum just before it hits the ground?

A) 1.18 kg∙m/s B) 0.429 kg∙m/s C) 4.21 kg∙m/s D) 3.24 kg∙m/s

63) A batter hits a 0.140-kg baseball that was approaching him at 40.0 m/s and, as a result, the ball leaves the bat

at 30.0 m/s in the direction of the pitcher. What is the magnitude of the impulse delivered to the baseball?

A) 9.80 Ns B) 5.60 Ns C) 1.40 Ns D) 7.00 Ns

64) Two ice skaters push off against one another starting from a stationary position. The 45-kg skater acquires a

speed of 0.375 m/s. What speed does the 60-kg skater acquire?

A) 0 m/s B) 0.500 m/s C) 0.375 m/s D) 0.281 m/s

65) A railroad car of massm and speedv collides and sticks to an identical railroad car that is initially at rest.

After the collision, the kinetic energy of the system

A) is the same as before. B) is one quarter as much as before.

C) is half as much as before. D) is one third as much as before.

566) An inelastic collision of two objects is characterized by the following.

A) Total momentum of the system is conserved.

B) Total kinetic energy of the system remains constant.

C) Both A and B are true.

D) Neither A nor B are true.

67) A mass of 2 kg traveling at 3 m/s undergoes a one-dimensional elastic collision with a group of four 1-kg

masses that are at rest in contact with each other and lined up in the same direction as the velocity of the

2-kg mass. As a result of the collision

A) the 2-kg mass and the ﬁve other masses travel at 1 m/s.

B) the 2-kg mass comes to a stop and one of the 1-kg masses takes off at 6 m/s.

C) the 2-kg mass comes to a stop and three of the 1-kg masses take off at 2 m/s.

D) the 2-kg mass comes to a stop and two of the 1-kg masses take off at 3 m/s.

68) An elastic collision of two objects is characterized by the following.

A) Total momentum of the system is conserved.

B) Total kinetic energy of the system remains constant.

C) Both A and B are true.

D) Neither A nor B are true.

69) An assault riﬂe ﬁres an eight-shot burst in 0.40 s. Each bullet has a mass of 7.5 g and a speed of 300 m/s as it

leaves the gun. What is the average recoil force on the gun during that burst?

A) 2.0 N B) 45 N C) 5.6 N D) 16 N

70) The SI unit of work is expressed as

A) newton/second. B) watt. C) joule. D) newton.

71) A person carries a mass of 10 kg and walks along the +x-axis for a distance of 100m with a constant velocity

of 2 m/s. What is the work done by this person?

A) 20 J B) 0 J

C) 200 J D) None of the other choices is correct.

72) A person applies a constant force of 20 N to a rock of 1000 kg. For 20 seconds. What is the work done by this

person if the rock does not move at all by this applied force?

A) 20,000 J B) 400 J C) 0 J D) 1000 J

73) A person lifts a mass of 20.0 kg vertically upwards at a constant speed of 0.200 m/s through a distance of

0.800 m. What is the work done by the person?

A) 16.0 J B) 3.20 J

C) 156 J D) None of the other choices is correct.

74) Which object has larger kinetic energy: a 500-kg object moving with a speed of 40 m/s or 1000-kg object

moving at 20 m/s?

A) Both have same kinetic energy. B) Kinetic energy is independent of mass.

C) the 500-kg object moving at 40 m/s D) the 1000-kg object moving at 20 m/s

75) An object of mass 10.0 kg is initially at rest. A 100 N force causes it to move horizontally through a distance

of 6.00 m. What is the change in the kinetic energy of this object?

A) 200 J B) 600 J C) 60.0 J D) 0 J

676) An object of mass 4 kg is thrown vertically upwards from ground level with an initial speed of 20 m/s.

Ignore friction and useg = 10 m/s

2

. What is the kinetic energy of the object as it reaches its maximum height?

A) 80 J B) 800 J C) 200 J D) 0 J

77) A spring with a spring constant of 2500 N/m. is stretched 4.00 cm. What is the work required to stretch the

spring?

A) 3.00 J B) 4.00 J C) 2.00 J D) 0 J

78) An object of mass 20 kg is raised vertically through a distance of 8.0 m above ground level. Usingg = 10 m/s

2

what is the potential energy of this object at this position?

A) 160 Nm B) 1600 Nm C) 1600 N/m D) 160 N/m

79) Swimmers at a water park have a choice of two frictionless water slides (see ﬁgure). Although both slides

drop over the same height, h, slide 1 is straight while slide 2 is curved, dropping quickly at ﬁrst and then

leveling out.

How does the speedv 1 of a swimmer reaching the end of slide 1 compares withv 2 , the speed of a

swimmer reaching the end of slide 2?

A) v 1 = v 2

B) v 1 < v 2

C) v 1 > v 2

D) No simple relationship exists betweenv 1 andv 2.

80) Two identical balls are thrown from the top of a building with the same speed. Ball 1 is thrown horizontally,

while ball 2 is thrown at an angle θ above the horizontal. Neglecting air resistance, which ball will have the

greatest speed when hitting the ground below?

A) Ball 1

B) Ball 2

C) There is not enough data to answer the question.

D) Both balls reach the ground with the same speed.

781) Swimmers at a water park have a choice of two frictionless water slides (see ﬁgure). Although both slides

drop over the same height, h, slide 1 is straight while slide 2 is curved, dropping quickly at ﬁrst and then

leveling out.

If t

1

is the time that the swimmer on slide 1 reaches the bottom and t

2

is the time that the other swimmer

reaches the bottom of slide 2., then how does t

1

compare with t

2

?

A) t

1

= t

2

B) t

1< t

2

C) t

1> t

2

D) No simple relationship exists between t

1

and t

2

.

82) An object is moving in a circular path with an angular speed of 1.52 rad/s. How long does it take the object

to complete one revolution?

A) 4.77 s B) 2.07 s C) 4.13 s D) 118 s

83) Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than

child B. Which child has the larger angular speed?

A) Child A

B) Child B

C) They have the same angular speed.

D) There is not enough information given to answer the question.

84) Two children are riding on a merry-go-round. Child A is at a greater distance from the axis of rotation than

child B. Which child has the larger centripetal acceleration?

A) Child A

B) Child B

C) They have the same centripetal acceleration.

D) There is not enough information given to answer the question.

85) A child is riding a merry-go-round which completes one revolution every 8.36 s. The child is standing 4.65

m from the center of the merry-go-round. What is the tangential speed of the child?

A) 5.64 m/s B) 0.556 m/s C) 1.80 m/s D) 3.49 m/s

86) A soccer ball whose radius is 11 cm rolls a distance of 10 m in 3.50 s. What is the angular speed of the ball?

A) 26 m/s B) 39 m/s C) 13 m/s D) 52 m/s

87) A disk, a hoop, and a sphere are released at the same time at the top of an inclined plane. They all roll

without slipping. In what order do they reach the bottom?

A) hoop, sphere, disk B) disk, hoop, sphere

C) sphere, disk, hoop D) hoop, disk, sphere

88) A compact disk rotates at 210 revolutions per minute. What is its angular speed in rad/s?

A) 11.0 rad/s B) 69.1 rad/s C) 22.0 rad/s D) 660 rad/s

889) In simple harmonic motion, the speed is greatest at that point in the cycle when

A) the potential energy is a maximum.

B) the magnitude of the acceleration is a minimum.

C) the displacement is a maximum.

D) the magnitude of the acceleration is a maximum.

90) If the amplitude of the motion of a simple harmonic oscillator is doubled, by what factor does the frequency

of the oscillator change?

A) 2 B) 1 C) 1/2 D) 4

91) A mass is attached to a spring and oscillates with a periodT. If the mass is doubled, what is the new period?

A) T/2 B) T/ 2 C) T 2 D) 2T

92) A massm is suspended from the ceiling of an elevator by a spring of force constantk. When the elevator is at

rest, the period of the mass isT. How does the period of the mass change when the elevator moves upward

with constant acceleration?

A) It increases.

B) It does not change.

C) It decreases.

D) It depends on how much you stretch the spring.

93) How much work is required to stretch a spring 25.2 cm if its force constant is 12.3 N/m?

A) 0.381 J B) 1.05 J C) 0.391 J D) 3.10 J

94) A vertical spring has a mass hanging from it, which is displaced from the equilibrium position and begins to

oscillate. At what point does the system have the least potential energy?

A) at the highest point B) at the lowest point

C) at the point where the spring is unstretched D) at the equilibrium point

95) The total mechanical energy of a simple harmonic oscillator is

A) zero when it reaches the maximum displacement.

B) a maximum when it passes through the equilibrium point.

C) constant.

D) zero as it passes the equilibrium point.

96) What is the length of a simple pendulum with a period of 2.00 s?

A) 19.6 m B) 0.994 m C) 0.873 m D) 1.62 m

97) Grandfather clocks are designed in a way that the weight at the bottom of the pendulum can be moved up or

down by turning a small screw. Suppose you have a grandfather clock at home that runs fast. Should you

turn the adjusting screw so as to raise the weight or lower the weight?

A) Raise it.

B) Lower it.

C) It doesn't matter if you raise or lower the weight, as long as you displace it by the right amount.

D) Raising or lowering the weight doesn't help, the screw is there so that you can add or take away

weight.

98) A harmonic wave has a wavelength of 2.0 m and a frequency of 5.0 Hz. What is the speed of the wave?

A) 0.4 m/s B) 0.10 m/s C) 10 m/s D) 2.5 m/s

999) A 15.0-m rope is pulled taut with a tension of 140 N. It takes 0.545 s for a wave to propagate along the rope.

What is the mass of the rope?

A) 2.77 kg B) 5.09 kg C) 3.19 kg D) 1.67 kg

100) You wish to double the speed of a wave in a string by tightening it. By what factor must you increase the

tension in the string?

A) 2 B) 4

C) 2 D) None of the above

101) The pitch of a sound is determined by

A) the speed. B) the amplitude. C) the wavelength. D) the frequency.

102) For the second-order maximum to occur in Young's two-slit experiment, what is the phase difference

between the light from the two sources?

A) 90° B) 270° C) 360° D) 180°

103) Seven seconds after a brilliant ﬂash of lightning, thunder shakes the house. How far was the lightning strike

from the house?

A) About one kilometer away B) Much closer than one kilometer

C) About two kilometers away D) Much farther away than two kilometers

104) A car horn emits a frequency of 400 Hz. A car traveling at 20.0 m/s sounds the horn as it approaches a

stationary pedestrian. What frequency does the pedestrian hear? The speed of sound in air is 343 m/s.

A) 375 Hz B) 400 Hz C) 450 Hz D) 425 Hz

105) A car horn emits a frequency of 400 Hz. A car traveling at 20.0 m/s sounds the horn as it goes away from a

stationary pedestrian. What frequency does the pedestrian hear? The speed of sound in air is 343 m/s.

A) 422 Hz B) 378 Hz C) 411 Hz D) 389 Hz

106) Two in-phase loudspeakers are 3.00 m apart. They emit sound with a frequency of 490 Hz. A microphone is

placed half-way between the speakers and then moved along the line joining the two speakers until the ﬁrst

point of constructive interference is found. At what distance from that midpoint is that ﬁrst point? The speed

of sound in air is 343 m/s.

A) 0.700 m

B) 0.350 m

C) 0.175 m

D) There is no point in that line where constructive interference occurs.

107) Two waves of equal amplitude and frequency arrive in phase at a certain point A. The resultant wave at

point Ais

A) a wave of zero amplitude.

B) a wave of the same frequency and twice the amplitude of the two incoming waves.

C) a wave of the same frequency and amplitude as the two incoming waves.

D) a wave of the same amplitude and twice the frequency of the incoming waves.

108) The wavelengths corresponding to the harmonics of a string with ﬁxed ends can be found by saying that the

length of the string must be equal to

A) an integer number of half-wavelengths. B) an odd number of quarter-wavelengths.

C) an odd number of half-wavelengths. D) an integer number of wavelengths.

10109) An organ pipe, open at both ends, is 5.20 m long. What is its fundamental frequency? The speed of sound in

air is 343 m/s.

A) 33.0 Hz B) 99.0 Hz C) 16.5 Hz D) 66.0 Hz

110) Two tuning forks have frequencies of 440 and 522 Hz. What is the beat frequency if both are sounding

simultaneously?

A) 962 Hz B) 41 Hz C) 82 Hz D) 431 Hz

111) The reason that you do not observe a Doppler shift when you listen to the car radio when you travel in your

car is that

A) the speed of the car is too slow compared to the speed of sound.

B) there is a Doppler shift but we don't notice it.

C) the air inside the car is moving at the same speed as the car.

D) the source and observer are moving at the same speed.

112) By what amount does the intensity level decrease when you triple your distance from a source of sound?

A) 4.8 dB B) 6.0 dB C) 9.5 dB D) 3.0 dB

113) Two people are talking at a distance of 3.0 m from where you are and you measure the sound intensity as 1.1

×10

-7 W/m2

. Another student is 4.0 m away from the talkers. What sound intensity does the other student

measure?

A) 6.2 ×10

-8 W/m2 B) 2.5 ×10

-8 W/m2 C) 8.3 ×10

-8 W/m2 D) 1.5 ×10

-7 W/m2

114) The sound of 40 decibels is

A) 10 times as intense as the sound of 20 decibels.

B) 1000 times as intense as the sound of 20 decibels.

C) 100 times as intense as the sound of 20 decibels.

D) twice as intense as the sound of 20 decibels.

115) The number of protons in the nucleus of an electrically neutral atom is equal to

A) the number of neutrons in the nucleus.

B) None of the other choices is correct.

C) the number of electrons in the nucleus.

D) the number of electrons surrounding the nucleus.

116) The charge on the proton is the same as

A) the charge on the electron.

B) the charge on the atom.

C) the charge on the electron, but of the opposite sign.

D) the charge on the neutron.

117) When the distance between the two charges is doubled, the force between them is

A) doubled. B) reduced by a factor of 2.

C) reduced by a factor of 4. D) quadrupled.

11118) An electron and a positron are released simultaneously from rest and start to move towards each other

because of the attractive Coulomb force between them. (Note: A positron is the antiparticle of the electron,

being in all aspects identical to the electron except in the sign of its electrical charge. The charge of the

positron is +e, while that of the electron is -e.) They are initially separated by a distanced. The two particles

eventually collide. When they collide,

A) they are closer to the electron's initial position.

B) Not enough data is given to predict where they collide.

C) they are at the midpoint of their initial separation.

D) they are closer to the positron's initial position.

119) A point chargeQ = 6.00 ×10

-9 C is placed at the origin of anx-y coordinate system. What is the electric ﬁeld

intensityE at a distance of x = 30 cm from this charge? (Use k = 9 ×10

9 Nm2/C2

.)

A) 500 N/C B) 600 N/C C) 400 N/C D) 300 N/C

120) A charged particle traveling along the +x axis enters an electric ﬁeld directed vertically upward along the

+y-axis. If the charged particle experiences a force downward because of this ﬁeld, what is the sign of the

charge on this particle?

A) It is positive. B) It is negative.

C) It is neutral. D) None of the other choices is correct.

121) A charged rod carrying a negative charge is brought near two spheres that are in contact with each other but

insulated from the ground. If the two spheres are then separated, what kind of charge will be on the spheres?

A) The sphere near the charged rod becomes negative and the other becomes positive.

B) The sphere near the charged rod becomes positive and the other becomes negative.

C) The spheres do not get any charge.

D) None of the other choices is correct.

122) Which one of the following is the correct unit for electric current?

A) A/s B) C/s C) J/s D) V/s

123) The potential difference between the ends of a resistor is 9 V when a current of 1 A ﬂows through it. What is

the value of that resistor?

A) 9 Ω B) 9 Ω s C) 9 V/s D) 9 V∙s

124) A 200-W light bulb is connected across 110 V. What current will ﬂow through this bulb?

A) 0 A B) 1.8 A C) 0.60 A D) 0.90 A

125) A 100-W light bulb is connected to a 110-V source. What current ﬂows through the lamp?

A) 0.91 A B) 3.3 A C) 1.1 A D) 2.2 A

126) Four resistors of 20 Ω, 40 Ω, 60 Ω, and 80Ω are connected across a DC voltage source. If the current through

this circuit is 0.5 A, what is the voltage applied to this circuit?

A) 60 V B) 80 V C) 100 V D) 40 V

127) A 100-V DC signal is applied to a series circuit composed of four equal resistors 10 Ω each. What is the

voltage across each resistor?

A) 25 V B) 15 V C) 20 V D) 10 V

12128) Four resistors of 20 Ω, 40 Ω, 60 Ω, and 80Ω are connected across a 50-V DC source. What is the current

through this circuit?

A) 4 A B) 0.50 A C) 0.25 A D) 0.75 A

129) An airplane starts from rest and accelerates at 10.8 m/s

2

. What is its speed at the end of a 400 m-long

runway?

A) 93.0 m/s B) 37.0 m/s C) 65.7 m/s D) 4320 m/s

130) A car is moving with a speed of 32.0 m/s. The driver sees an accident ahead and slams on the brakes, giving

the car a deceleration of 3.50 m/s

2

. How far does the car travel after the driver put on the brakes before it

comes to a stop?

A) 146 m B) 9.14 m C) 112 m D) 4.57 m

131) An astronaut stands by the rim of a crater on the moon, where the acceleration of gravity is 1.62 m/s

2

. To

determine the depth of the crater, she drops a rock and measures the time it takes for it to hit the bottom. If

the depth of the crater is 120 m, how long does it take for the rock to fall?

A) 3.04 s B) 32.1 s C) 29.3 s D) 12.2 s

132) Which one of the following is true of two waves to meet constructively?

A) The phase difference between the two waves is 5π/2.

B) The phase difference between the two waves is 2π.

C) The phase difference between the two waves is π/4.

D) The phase difference between the two waves is π/2.

133) One of the harmonics of a column of air open at one end and closed at the other has a frequency of 448 Hz

and the next higher harmonic has a frequency of 576 Hz. How long is the air column? The speed of sound in

air is 343 m/s.

A) 1.00 m B) 1.34 m C) 0.335 m D) 0.670 m

134) A car is traveling at 26.0 m/s when the driver suddenly applies the brakes, giving the car a constant

deceleration. The car comes to a stop in a distance of 120.0 m. How fast was the car moving when it was 60.0

m past the point where the brakes were applied?

A) 15.0 m/s B) 12.1 m/s C) 22.5 m/s D) 18.4 m/s

135) An object is thrown upwards with a speed of 15 m/s. How long does it take it to reach a height of 6.0 m on

the way up?

A) 2.4 s B) 3.1 s C) 0.47 s D) 1.2 s

A mass of 1.0 kg is pushed against a spring with a spring constant of 25 N/m. As a result, the spring is compressed by

20 cm. The mass is then released.

136) What is the kinetic energy of the mass after the mass is released and it is no longer in contact with the

spring?

A) 0.20 J B) 5.0 J C) 0.50 J D) 10 J

137) What is the amount of potential energy acquired by the spring when it is compressed?

A) 0.50 J B) 5.0 J C) 0.20 J D) 10 J

13Figure 2-1

138) Refer to Figure 2-1. If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the

magnitude of your displacement?

A) 6.5 km B) 10.5 km C) 2.5 km D) 9.0 km

139) Refer to Figure 2-1. If you start from the Bakery, travel to the Cafe, and then to the Art Gallery, what is the

distance you have traveled?

A) 2.5 km B) 6.5 km C) 0 km D) 10.5 km

Figure 2-2

140) Figure 2-2 represents the position of a particle as it travels along thex-axis. What is the average speed of the

particle between t = 1 s and t = 4 s?

A) 1.0 m/s B) 0.50 m/s C) 1.3 m/s D) 0.67 m/s

Figure 2-4

141) Figure 2-4 shows the velocity-versus-time graph for a basketball player traveling up and down the court in

a straight-line path. Find the total distance run by the player in the 10 s shown in the graph.

A) 20 m B) 14 m C) 18 m D) 16 m

14142) Figure 2-4 shows the velocity-versus-time graph for a basketball player traveling up and down the court in

a straight-line path. Find the net displacement of the player for the 10 s shown on the graph.

A) 16 m B) 18 m C) 14 m D) 20 m

Figure 8-1

An object of mass 2 kg is held at the top of a triangular wedge as shown in Figure 8-1, and then released. The

reference level for potential energy is at the base of the triangle. Neglect friction and use g = 10 m/s

2

.

143) Refer to Figure 8-1. What is the amount of work done by the gravitational force as the object comes to the

bottom of the wedge?

A) 60 J B) 10 J C) 0 J D) 60 N/m

Figure 8-3

A roller coaster of mass 80.0 kg is moving with a speed of 20.0 m/s at position A as shown in Figure 8-3. The vertical

height at position A above ground level is 200 m. Neglect friction and use g = 10.0 m/s

2

.

144) What is the total energy of the roller coaster at point B?

A) 16.4 × 10

3

J B) 16.4 × 10

4

J C) 17.6 × 10

4

J D) 20.2 × 10

3

J

145) What is the total energy of the roller coaster at point A?

A) 17.6 × 10

4

J B) 16.0 × 10

3

J C) 20.2 × 10

3

J D) 16.0 × 10

4

J

15SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.

146) (4 points) A roller-coaster car speeds down a hill past point A where R1 = 9.2 m and then rolls up a hill past

point B where R2 = 15.4 m, see the ﬁgure in appendix A

(a) The car has a speed of 19.6 m/s at point A. if the track exerts a normal force on the car of 2.19 x10

4 N at

this point, what is the mass of the car?

(b) What is the maximum speed the car can have at point B for the gravitational force to hold it on the track?

147) ( 4 points) A window washer is standing on a scaffold supported by a vertical rope at each end. The scaffold

weighs 203 N and is 3.20 m long. What is the force each rope exerts on the scaffold when the 670 N worker

stands 1.00 m from one end of the scaffold?

16148) ( 4 points) A mass-spring system oscillates with an amplitude of 3.4 cm. The spring constant is 260 N/m and

the mass is 0.50 kg.

(a) Calculate the mechanical energy of the mass-spring system.

(b) Calculate the maximum acceleration of the mass-spring system.

149) (3 Points) A batter hits a 0.140-kg baseball that was approaching him at 30.0 m/s and, as a result, the ball

leaves the bat at 40.0 m/s in the direction of the pitcher. The ball remains in contact with the bat for 2.0 ms.

What is the average force exerted by the bat?

17150) ( 2 points) Express an angular speed of 33.3 rpm in rad/s.

18Answer Key

Testname: REVIEW HONORS PHYSICS WEB

1) FALSE

2) FALSE

3) TRUE

4) TRUE

5) FALSE

6) FALSE

7) TRUE

8) FALSE

9) TRUE

10) TRUE

11) TRUE

12) TRUE

13) FALSE

14) TRUE

15) FALSE

16) TRUE

17) FALSE

18) TRUE

19) TRUE

20) TRUE

21) FALSE

22) TRUE

23) FALSE

24) TRUE

25) FALSE

26) FALSE

27) FALSE

28) TRUE

29) FALSE

30) TRUE

31) FALSE

32) TRUE

33) TRUE

34) TRUE

35) D

36) A

37) D

38) D

39) D

40) A

41) C

42) C

43) A

44) B

45) D

46) D

47) C

48) D

49) C

19Answer Key

Testname: REVIEW HONORS PHYSICS WEB

50) A

51) B

52) C

53) A

54) D

55) B

56) B

57) D

58) D

59) C

60) C

61) C

62) C

63) A

64) D

65) C

66) A

67) D

68) C

69) B

70) C

71) B

72) C

73) C

74) C

75) B

76) D

77) C

78) B

79) A

80) D

81) C

82) C

83) C

84) A

85) D

86) A

87) C

88) C

89) B

90) B

91) C

92) B

93) C

94) D

95) C

96) B

97) B

98) C

20Answer Key

Testname: REVIEW HONORS PHYSICS WEB

99) A

100) B

101) D

102) C

103) C

104) B

105) B

106) B

107) B

108) A

109) A

110) C

111) D

112) C

113) A

114) C

115) D

116) C

117) C

118) C

119) B

120) B

121) B

122) B

123) A

124) B

125) A

126) C

127) A

128) C

129) A

130) A

131) D

132) B

133) B

134) D

135) C

136) C

137) A

138) C

139) D

140) C

141) A

142) B

143) A

144) C

145) A

146) a) 425 kg b) 12.3 m/s

147) 311 N and 562 N

21Answer Key

Testname: REVIEW HONORS PHYSICS WEB

148)

149) 4900 N

150) 3.49 rad/s

22

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