A95 kg fullback, running at 8.2 m/s, collides in midair with a 128 kg defensive tackle moving in the opposite direction. both players end up with zero speed.
a) what was the change in the fullbacks momentum?
b) what was the change in the defensive momentum?
c) what was the defensive tackle's original momentum?
d) how fast was the defensive tackle moving origianally?

Asolid cylinder and a cylindrical shell have the same mass, same radius, and turn on frictionless, horizontal axles. the cylindrical shell has light-weight spokes connecting the shell to the axle. a rope is wrapped around each cylinder and tied to blocks of equal masses that are held the same height above the ground. both blocks are released simultaneously. the ropes do not slip. which block hits the ground first? or is it a tie?