Question

Which of the following has a higher magnitude and why: Sliding friction or rolling friction

Answer 1

We know that frictional force of a body is directly proportional to the normal reaction of the body with the ground.

In case of a body sliding over the ground, the area of contact at a particular time is higher, hence higher normal reaction.

In case of a body rolling over the ground, the area of contact at a particular time is lesser, hence lower normal reaction.

This is why sliding friction is greater than rolling friction.