in a movie stunt, a 65 kg skier starts from a rest postion at the top of a hill 30 m high. she slides down the hill to the bottom, where she collides with a 45 kg stationary skier. the collision is completely inelastic. find the fiinal velocity of the skiers. ATTEMPT. i know i have to use m1v1+ m2v2= (m1+m2)v but i'm not sure about what values to use. and why am i given the height?