Rolling: A uniform disk, a uniform hoop, and a uniform solid sphere are released at the same time at the top of an inclined ramp. They all roll without slipping. In what order do they reach the bottom of the ramp?
A) disk, hoop, sphere
B) hoop, sphere, disk
C) sphere, disk, hoop
D) sphere, hoop, disk
E) hoop, disk, sphere

Question

Quizplus · Accepted Answer

The solid sphere will reach the bottom first because it has the highest rotational inertia and will therefore experience the lowest acceleration down the ramp. The disk will reach the bottom second because it has a lower rotational inertia than the hoop. The hoop will reach the bottom last because it has the lowest rotational inertia and will experience the highest acceleration down the ramp, but it will take longer to reach the bottom due to its larger circumference. Therefore the correct order is sphere, disk, hoop.

Rolling: a Uniform Disk, a Uniform Hoop, and a Uniform