4 Newton's Laws of Motion - BC Science Physics 11

4.4 Review Questions
1. What is the momentum of a 75 g mouse running
across the floor with a velocity of 2.6 m/s?
2. What is the impulse of a 55 N force exerted over a
time interval of 1.0 ms?
3. A 0.060 kg rifle bullet leaves the muzzle with a
velocity of 6.0 × 10 2 m/s. If the 3.0 kg rifle is held
very loosely, with what velocity will it recoil?
4. A 53 kg skateboarder on a 2.0 kg skateboard
is coasting along at 1.6 m/s. He collides with a
stationary skateboarder of mass 43 kg, also on a
2.0 kg skateboard, and the two skateboarders coast
off in the same direction that the first skateboarder
was travelling.What velocity will the combined
skateboarders now have?
5. What impulse is needed to change the velocity of a
10.0 kg object from 12.6 m/s to 25.5 m/s in a time of
5.00 s? How much force is needed?
6. A 1.5 × 10 3 kg car travelling at 44 m/s collides
head-on with a 1.0 × 10 3 kg car travelling at 22 m/s
in the opposite direction. If the cars stick together
on impact, what is the velocity of the wreckage
immediately after impact? (Hint: Let the velocity of
the second car be –22 m/s, since it is moving in a
direction opposite to the first car.)
7. (a) What impulse must be imparted by a baseball
bat to a 145 g ball to change its velocity from
40.0 m/s to –50.0 m/s?
(b) If the collision between the baseball and the
bat lasts 1.00 ms, what force was exerted on the
ball? (1 ms = 10 –3 s)
126 Chapter 4 Newton’s Laws of Motion © Edvantage Interactive 2012 ISBN 978-0-9864778-3-6