A box slides down a frictionless incline,and a hoop rolls down another incline.Both inclines have the same height,and both the box and the hoop have the same mass.If both objects start from rest,upon reaching the bottom of the incline which one will have the greater kinetic energy and which one will have the greater speed?
A)The box will have both the greater kinetic energy and the greater speed.
B)The hoop will have both the greater kinetic energy and the greater speed.
C)Both will have the same kinetic energy,but the hoop will have the greater speed.
D)Both will have the same kinetic energy,but the box will have the greater speed.

Question

Quizplus · Accepted Answer

Both objects will have the same kinetic energy because they start from the same height and have the same mass, thus the same potential energy is converted to kinetic energy. However, the box will have the greater speed because the hoop's kinetic energy is divided between translational and rotational motion, while the box's kinetic energy is purely translational.

A Box Slides Down a Frictionless Incline,and a Hoop Rolls