A running back with a mass of 80 kg and speed 8 m/s collides with, and is held by, a 120 kg defensive tackle going in the opposite direction. How fast must the tackle be going before the collision for their speed afterward to be zero?

A 980-kg sports car collides into the rear end of a 2500-kgkg SUV stopped at a red light. The bumpers lock, the brakes are locked, and the two cars skid forward 2.9 mm before stopping. The police officer, estimating the coefficient of kinetic friction between tires and road to be 0.80, calculates the speed of the sports car at impact. Question: What was the speed sports car at impact? v=??

A 1.5x105 kg barge is floating downriver in a fog with a velocity of i = m/s when it collides with a second barge with a mass of 3.0x105 kg heading across the river with a velocity of i = m/s. Immediately after impact, the second barge is headed 20° downriver with a speed of 4.5 m/s. Assume the current is negligible in this part of the river. a. What is the velocity of the second barge immediately after impact (in vector form)? b. Use conservation of momentum to find the velocity of the first barge immediately after impact (in vector form)? c. Was the collision elastic? If not, what was the change in kinetic energy? 20 Downriver

A train engine’s mass is 22500 kg and is moving at 25 m/sec, and hits an empty train car with a mass of 7500 kg. What velocity would the empty train car have after impact? (no friction in this system, of course)

A soccer player hits a ball incoming with 2.4 m/s in the West direction. After the kick, the ball changes its direction by 90 degrees and start moving with 1.2 m/s in the North. What is the average force applied if the interaction time is 0.2 seconds and the mass of the ball is 0.3 kg.

The figure shows two 21.6 kg ice sleds that are placed a short distance apart, one directly behind the other. A 3.99 kg cat initially standing on one sled jumps to the other one and then back to the first. Both jumps are made at a speed of 3.07 m/s relative to the ice. What are the final speeds of (a) the first sled and (b) the other sled? (a) Number (b) Number i Units Units SD

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A 32,912 kg freight car is coasting at .84 m/s with negligble friction under a hopper that dumps 118,359 kg of scrap metal into it. (a) What is the final velocity (in m/s) of the loaded freight car? Number (b) What is the magnitude of the kinetic energy lost in this process of loading the freight car? Number

Yong had stopped his cart which has a mass of 500 kg  just before a 30degree hill covered in ice. He was stuck from behind by a 1500 kg coach with a mass of1500 kg which is travelling at 20 m/s. The two vehicles stuck together and slid up the hill. How far up the slope did they go?