Physics 101 Practice Quiz 3

1) Vector A has a magnitude of 16.0 m and is pointing eastward. It is rotated 110.0° clockwise. The
component of this vector along west is
A) 15.0 m.
B) 5.47 m.
C) 18.7 m.
D) 12.4 m.
Answer: B

2) When vectors A and B are added together they form vector C and these vectors satisfy the
relationship A2 + B2 = C2. Which statement is true for these vectors?
A) Vectors A  and B must be parallel.
B) Vectors A and B must be anti-parallel.
C) Vectors A and B must have the same magnitudes.
D) Vectors A and B must be perpendicular.
Answer: D



3) A displacement vector is 34.0 m in length and is directed 60.0° east of north. What are the components
of this vector?
choice Northward component Eastward component
1                       29.4 m               17.0 m
2                      18.2 m                28.1 m
3                      22.4 m               11.5 m
4                      17.0 m              29.4 m
Answer: 4


4) The magnitudes of the four vectors shown in Figure above are given as follows: A = 14.0 m; B = 12.0
m; C = 10.0 m and D = 6.0 m. The components of the vector sum of these four vectors are
choice x-component y-component
1 1.5 m 6.0 m
2 13.5 m 20.0 m
3 3.5 m 18.0 m
4 -2.9 m -18.0 m
A) Choice 1
B) Choice 2
C) Choice 3

D) Choice 4
Answer: C


5) The components of vectors M and N are as follows: M (1, -1) and N (2, 4). The components of the
resultant vector M - N are given by
A) (-1, -5).
B) (3, 3).
C) (1, -5).
D) (0, 4).
Answer: A


6) Refer to Figure 3-3. The components of the vector sum are given by
choice x-component y-component
1 3.73 cm 2.20 cm
2 -3.73 cm 2.20 cm
3 -2.27 cm 0 cm
4 2.27 cm 0 cm
A) Choice 1
B) Choice 2
C) Choice 3
D) Choice 4
Answer: B


7) A plane has an airspeed of 142 m/s. A 30.0 m/s wind is blowing southward at the same time as the plane
is flying. What must be the direction of the plane in order to move due east relative to the ground?
A) 78.1° north of east
B) 11.9° north of east
C) 77.8° north of east
D) 12.2° north of east
Answer: B


8) Refer to Figure above. Vector S as expressed in terms of vectors M and N is given by
A) M + N
B) M - N
C) M.
D) None of the other choices is correct.
Answer: B


9) Three vectors have equal magnitudes and make 120° with each other. We can say that
A) the magnitude of the resultant is three times the magnitude of the component vectors.
B) the magnitude of the resultant is more than three times the magnitude of each component vector.
C) the resultant is zero.
D) the magnitude of the resultant is equal to the magnitude of the component vectors.
Answer: C


10) Vector B is obtained by rotating vector A counterclockwise by 270°. The components of B
will
A) have the same signs as those of A
B) have opposite signs as those of A
C) The x-components will have opposite signs but the y-components will not.
D) It depends on the quadrant where A is.
Answer: D