# Force exerted by a rolling body

1. Oct 12, 2011

### sodaboy7

Lets consider a block of mass m, sliding down an inclined surface (no friction) at an angle ∅ with ground. The force exerted by this block on the inclined surface is mgcos∅ which is perpendicular to it. Now consider a cylinder of same mass m and rolling (without slipping) down the same plane. What will be the force exerted by the rolling cylinder on inclined surface? will it be mgcos∅ or something more than that due to its rolling motion.

2. Oct 12, 2011

### rcgldr

If the surface is frictionless, the cylinder isn't rolling, since it will have linear acceleration, but not angular acceleration. If there's friction, then that will produce an upwards force in the sin(θ) direction.

3. Oct 12, 2011

### sodaboy7

in case of block its frictionless and in case of rolling its not. I am asking about forces perpendicular to surface not along the surface. So will there be any force other than mgcos∅?

4. Oct 12, 2011

### Staff: Mentor

The normal force will be the same: mgcos∅

5. Oct 12, 2011

### rcgldr

Since's there's no component of acceleration in the direction of cos(θ), the component of force from gravity and the opposing normal force from the plane in the direction cos(θ) will be m g cos(θ) (as Doc Al just posted), in either the sliding or the rolling case.

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