# Inclined cylinder torque problem

1. Jan 28, 2008

### yasar1967

1. On an inclined surface a cylinder can roll as long as the surface has friction. In order to stop it rolling one can apply a force opposing in direction of the surface thus cancelling the torque effect of friction force.
I understand if that force is applied tangential(not necessarily but away from CM) to cylinder creating a level arm with center of mass thereby creating the negative torque of friction.
How about applying that force parallel to the surface and in the same direction of friction and crossing over Center of Mass. As this force crossing the CM it should have no torque effect(just like Mgsin0) yet the rolling stops. Actually I did the experiment myself and saw it happened.
Only torque creating force is still the friction but yet the rolling stops.

I know that if you do not take into consideration the torque equations and go just with force equilibrium, one can say you cancel the the force of Mgsin0 together with friction and the cyclinder's linear motion stopped.

But how about in terms of rolling kinematics?

How can I justify that?

Last edited: Jan 28, 2008
2. Jan 29, 2008