1) A 10 kg car is moving at 44 m/s when it collides with a stationary 71 kg truck. The two cars interlock and move off at what speed

2) A 9 kilogram potato leaves a 155 kilogram cannon with a velocity of 283 m/s. What is the recoil velocity of the launcher?

3) A 994 kg truck moves to the right at 17 m/s and collides with a 700 kg car that is moving at 5 m/s. If the two vehicles stick together, what will their velocity be after the collision?

4) Steve loosely holds a 2.4 kg air rifle and fires a 0.3 kg bullet. The velocity of the bullet is 267.9 m/s. What is the recoil velocity of the rifle?

2 answers

momentum is conserved in all these problems

that is some BIG potato in #2
watermelon?
9 * 283 + 155 u = 0 which is the momentum before ignition.