Question

A tire of radius $R$ rolls on a flat surface with angular velocity $\omega$ and velocity $v$ as shown in the diagram. If $v>\omega R$, in which direction does friction from the tire act on the road?

• A. Towards downwards
• B. Towards upwards
• C. Towards the left
• D. Towards the right

Answer 1

Answer: (C)

Towards the left

The solution of this question can simply be understand by taking a situation of car driver, where at higher speed he applies sudden brakes, i.e. $v>\omega r$ and the tire rubs the road and we have rolling with forward slipping i.e., friction acting in opposite direction of $v$. (towards left in the above situation.)