Thursday, November 8, 2012

Ch 6 Collision Problems Solutions

(5)  Drops of rain fall perpendicular to the roof of a parked car during a rainstorm. The drops strike the roof with a speed of 20 m/s, and the mass of rain per second striking the roof is 0.066 kg/s.
(a) Assuming the drops come to rest after striking the roof, find the average force exerted by the rain on the roof.
magnitude 1 N
direction 2 ---Select--- upward downward

(b) If hailstones having the same mass as the raindrops fall on the roof at the same rate and with the same speed, how would the average force on the roof compare to that found in part (a)? (Assume the hailstones bounce back up off the roof.)

The magnitude would be double that in part (a).
The magnitude would be four times that in part (a).
The magnitude would be half that in part (a).
The magnitude would be the same as in part (a).


(9)   A 0.280 kg volleyball approaches a player horizontally with a speed of 15.0 m/s.  The player strikes the ball with her fist and causes the ball to move in the opposite direction with a speed of 22.0 m/s.

a) What impulse is delivered to the ball by the player?

b) If the players fist is in contact with the ball for 0.060 0 s, find the magnitude of the average force exerted on the players fist.

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