Dec13
Monday, December 13, 2010
8:05 AM
13. A 2.5 kg ball strikes a wall with a velocity of 8.5 m/s to the left. The ball bounces off with a velocity of 7.5 m/s to
the right. If the ball is in contact with the wall for 0.25 s, what is the constant force exerted on the ball by the wall?
(160 N to the right)
14. A football punter accelerates a 0.55 kg football from rest to a speed of 8.0 m/s in 0.25 s. What force does the
punter exert on the ball? (18 N)
15. A pole-vaulter falls from rest from a height of 5.0 m onto a foam rubber pad. The pole-vaulter comes to rest in
0.3 s after landing on the pad. Calculate the athlete velocity just before reaching the pad. Calculate the force
exerted on the athlete during the collision with the pad. (-9.9 m/s, 1815N)
Physics H1 Page 1
16. A 0.150 kg baseball moving 26 m/s is slowed to a stop by a catcher in 0.010s. What force did the catcher exert
on the ball? How far did the ball travel before coming to a stop? (-390N, 0.13 m)
Physics H1 Page 2