A solid sphere of radius R and mass m starts from rest at a height h and rolls down an incline without slipping. The ratio of translational to rotational kinetic energy at the bottom of the incline is
A) R/h.
B) 2R/5h.
C) 5R/2h.
D) 2/5.
E) 5/2.

Question

Quizplus · Accepted Answer

The translational kinetic energy (TKE) is (1/2)mv^2 and the rotational kinetic energy (RKE) for a solid sphere is (1/2)(2/5)mv^2 = (1/5)mv^2. The ratio of TKE to RKE is (1/2)mv^2 / (1/5)mv^2 = 5/2.

A Solid Sphere of Radius R and Mass M Starts