Two space ships collide in deep space. Spaceship P, the projectile, has a mass of 5M, while the target spaceship T has a mass of M. Spaceship T is initially at rest and the
collision is elastic. If the final velocity of T is 6.7 m/s, what was the initial velocity of
P?

A12-g wad of sticky clay is hurled horizontally at a 100-g wooden block initially at rest on a horizontal surface. the clay sticks to the block. after impact, the block slides 7.5 m before coming to rest. if the coefficient of friction between the block and the surface is 0.65, what was the speed of the clay immediately before the impact?