physics
posted by need help as soon as possible .
A solid ball and a hollow ball, each with a mass of 6 kg and radius of 0.1 m, start from rest and roll down a ramp of length 3 m at an incline of 31°. An ice cube of the same mass slides without friction down the same ramp.
What is the speed of the ice cube at the bottom of the incline?

(1/2) m v^2 = m g h = m g *3 sin 31
v = sqrt (2 g *3 sin 31)