# angular displacement

#### sake

Homework question help--

A ball inside a computer mouse has a radius of 1.0 cm. If the mouse moves 12 cm, find the angular displacement of the ball.

Thanks much.

#### physicsquest

PHF Helper
If the ball revolves once the ball moves a distance = circumference of the ball i.e 2 x pi x 1 = 2 pi cm. So when it travels a distance of 12 cmthe no of revs = 12 / 2 pi times. One revolution corresponds to an angular didplacement of 2 pi radians . So 12 / 2 pi radians will correspond to an angular displacement of (12 / 2 pi ) x 2 pi = 12 radians.