A2 kg mass moving to the right makes an elastic head-on collision with a 4 kg mass moving to the left at 4 m/s. the 2 kg mass reverses direction after the collision and moves at 3 m/s. the 4 kg mass moves 1m/s to the left. what was the initial velocity of the 2 kg mass?

Using the work energy theorem. what is the velocity of a 850kg car after starting at rest when 13,000j of work is done to it.

Which of the following are appropriate acceleration units?

The astronauts on the space shuttle flights experienced an acceleration of 29 m/s2 (about 3 "g's") during lift-off. what upward force must the astronaut's seat apply to the astronaut in order to cause this acceleration? assume the astronaut's mass is 70 kg, and compute this force when the acceleration is near the earth's surface so their weight equals latex: mg m g .