A hollow cylinder of mass M and radius R rolls down an inclined plane. A block of mass M easily slides down an identical inclined plane. Complete the following statement: If both objects are released at the same time from the top of their inclined planes,
A)the cylinder will reach the bottom first.
B)the block will reach the bottom first.
C)the block will reach the bottom with the greater kinetic energy.
D)the cylinder will reach the bottom with the greater kinetic energy.
E)both the block and the cylinder will reach the bottom at the same time.

Question

Quizplus · Accepted Answer

The block will reach the bottom first because its motion is solely determined by gravitational force, while the cylinder has to overcome both gravitational force and rotational inertia. Therefore, the block will have a greater acceleration while rolling motion of the cylinder will slow it down. The kinetic energy of the block will also be greater because it moves with a greater speed than the cylinder, and the kinetic energy of the cylinder will be partially converted into rotational energy.

A Hollow Cylinder of Mass M and Radius R Rolls