Aball is thrown upward and outward from the top edged of a 50 ft building it reaches its highest point 20 ft above and 10 ft out from the building. how far from the building is the ball when it hits the ground ?

In a game of pool, ball a is moving with a velocity v0 of magnitude v0 = 15 ft/s when it strikes balls b and c, which are at rest and aligned as shown. knowing that after the collision the three balls move in the directions indicated and assuming frictionless surfaces and perfectly elastic impact (that is, conservation of energy), determine the magnitudes of the velocities va, vb, and vc.