A solid sphere, a solid cylinder, and a hoop all have the same mass and radius. Each are sent down identical inclined planes starting from rest. Their kinetic energies at the bottom of the incline are Ksphere, Kcylinder, and Khoop. Which of the following is true?
A)Ksphere Kcylinder
B)Khoop Ksphere
C)Khoop Kcylinder
D)Kcylinder Khoop
E)No answer above is correct.

Question

A solid sphere, a solid cylinder, and a hoop all have the same mass and radius. Each are sent down identical inclined planes starting from rest. Their kinetic energies at the bottom of the incline are Ksphere, Kcylinder, and Khoop. Which of the following is true?
A)Ksphere > Kcylinder
B)Khoop > Ksphere
C)Khoop > Kcylinder
D)Kcylinder > Khoop
E)No answer above is correct.

Quizplus · Accepted Answer

All objects have the same mass and radius and start from rest, so they all have the same gravitational potential energy at the top. As they roll down without slipping, all potential energy is converted into kinetic energy. Therefore, Ksphere = Kcylinder = Khoop, making none of the given inequalities true.

A Solid Sphere, a Solid Cylinder, and a Hoop All