Question

A boy and his skateboard have a combined mass of 64 kg. If he is moving with a speed of 3.2 m/s, and collides with a stationary skateboarder whose mass (including his skateboard) is 96 kg, with what speed will the two skateboarders move immediately after the collision? assume they are hopelessly entangled, but their wheels point in the same direction

Answer 1

mv=(m+M)u
u=mv/(m+M)