1. An astronaunt is stuck in space (speed=0), and he is about 100 m from the spacestation. He needs to find a way to go towards the spacestation. he suddenly throws away a 2.00 kg wrench at 20 m/s in the other direction from the station. If his total mass is 200kg find

a) his speed right after throw away the wrench.

b) how long will take him to coast back to the ship.

2. A baseball player throw a 0.150kg baseball with a velocity of 20m/s. It is struck by the bat with an average force of 5000 N, the baseball flew off with 20.0 m/s in the opposite direction from the original velocity. Find

a) The change of mometum for the baseball.

b) How long were the bat and ball in contact? (show your work please)

3. The first car, 300-kg car is moving at 20.0 m/s east and hits from behind a second car, 800-kg moving at 12.0m/s traveling aslo east. The two car are stuck and they move together after the colision. Find the final velocity of the two car. Please show your work.

4. When you play with your toy gun, the gun has a spring. When the spring is compressed by 0.12m, the toy gun shots out a 0.010 kg pellet to a max height of 100m, a) What is the final gravitational potential energy of the pellet? b) What is the spring constant? Ignore air resistance. Please show your work

5. A small pellet (m=0.020 kg) travel with 50m/s went through a wood block that is 0.30 m thick. It comes out from the block moving at 15 m/s. a) Find the change in kinetic energy. b) Find the magnitude of the frictional force from the block. Please show your work.