## srijit 2 years ago does friction act to make the velocity of a purely rolling body constant by balancing the other net external torque?

1. Vincent-Lyon.Fr

What friction are you talking about? Air friction can act this way, or spinning friction about the axis of rotation.

2. srijit

spinning friction tangential to contact area

3. Vincent-Lyon.Fr

In case of pure rolling body on a fixed base, this force is a static friction force and its power is zero. Such a force will never balance any external torque. This is why all systems with rolling bodies can be seen as conservative and solved using mechanical energy conservation.

4. srijit

no i meant to say after an external torque is applied to a purely rolling body friction adjusts itself to prevent slipping of the point of contact..then after sometimes does the velocity becomes constant and friction ceases to act?

5. Vincent-Lyon.Fr

"no i meant to say WHILE an external torque is applied to a purely rolling body friction adjusts itself to prevent slipping of the point of contact" – Correct "..then after sometimes does the velocity becomes constant and friction ceases to act?" – If net external torque ceases to exist, velocity will be constant and, although friction is there, the friction force will be equal to zero.