A 0.20-kg rubber ball is dropped from the window of a building. It strikes the sidewalk below at 30 m/s and rebounds at 20 m/s. The change in momentum of the ball as a result of the collision with the sidewalk is (in kg}
10.0
6.0
4.0
2.0
1.0

A man, standing at rest on a horizontal frictionless floor, might get himself moving by:
walking
rolling
exhaling vertically
crawling slowly
throwing a shoe horizontally

A rifle of mass M is initially at rest but free to recoil. It fires a bullet of mass m and velocity v (relative to the ground). After firing, the velocity of the rifle (relative to the ground) is:
-mv
-Mv/m
-mv/M
-v
mv/M
 

Blocks A and B are moving toward each other along the x-axis. A has a mass of 2.0 kg and a velocity of 50 m/s, while B has a mass of 4.0 kg and a velocity of -25 m/s. They suffer an elastic collision and move off along the x axis. The kinetic energy transferred from A to B during the collision is:
0 J
2500 J
5000 J
7500 J
10000 J