a. Two hockey players heading in opposite directions on the rink collide, one with a body mass of 85 kg traveling at 4 m/s one way, and the other with a body mass of 75 kg traveling at 2.50 m/s in the opposite way. If the two players stick together and travel in the direction of the more massive player, what is their combined velocity after the collision?

b. In your car gently reversing, you collide with a curb for 0.50 s, reducing your momentum from 2,030 kg m/s to zero, what was the force of the curb on the car in N (put in the magnitude of the force, a positive number) to two significant digits?