A cylinder, released from the top of an inclined plane, rolls without sliding and reaches the bottom with speed vr. Another identical cylinder, released from the top of the same inclined plane, slides without rolling and reaches the bottom with speed vs. Then
When the cylinder rolls without sliding, the acceleration down the plane is
When the cylinder slides without rolling, the acceleration is
where is the inclination of the plane.
If h is the height of the inclined plane, their speeds on reaching the bottom are given by
Since , it follows that , which is choice (b).