A machine part has the shape of a solid uniform sphere of mass 255 g and diameter 4.50 cm . It is spinning about a frictionless axle through its center, but at one point on its equator it is scraping against metal, resulting in a friction force of 0.0200 N at that point. Find its angular acceleration. Let the direction the sphere is spinning be the positive sense of rotation. How long will it take to decrease its rotational speed by 20.0 rad/s ?

A machine part has the shape of a solid uniform sphere of mass 255 g and diameter 4.50 cm . It is spinning about a frictionless axle through its center, but at one point on its equator it is scraping against metal, resulting in a friction force of 0.0200 N at that point. Find its angular acceleration. Let the direction the sphere is spinning be the positive sense of rotation. How long will it take to decrease its rotational speed by 20.0 rad/s ?