Can you show work please..?

1. Joe is sledding down a snow hill when he collides with Mike half way down the hill. Joe and the sled have a mass of 65 kg and their velocity before the collision was 12 m/s. If Mike has a mass of 55 kg, what velocity would Joe, Mike, and the sled have after the collision?

2. A 3 kg cart is moving along when it strikes a 2 kg cart (initially at rest). The velocity of the two-cart combination after the collision is 4 m/s. Calculate the velocity of the 3 kg cart before the collision.

3. Tyler is standing at the 10-yard line waiting to catch the initial kick-off. The .75 kg football experiences a change in velocity of 12 m/s in .17 s when caught by Tyler. What force does Tyler apply on the football?

1 answer

1) assuming they stuck together after the collision?
Assuming that, momentum is conserved.
momentum before= momentum after
65*12+0=(65+55)V solve for V