Question

If the external force and the frictional force are acting on a body, which is in rest on the floor and are equal and opposite, then the frictional force is equal to:
(A) Rolling friction
(B) Sliding friction
(C) Static friction
(D) Both B and C

Answer 1

Hint Static friction comes into play when the body is stationary and a force is acting on it. If the force acting on the body is greater than the static friction of the body then it will move with some acceleration. If the external force is not able to overcome the static friction, then it cancels itself out with it and the body will not move.

Complete step by step solution
Rolling friction is the friction when the body is rotating with some angular velocity without slipping. This means that after 1 revolution it should cover a path equal to its perimeter. Rolling friction acts on a single point which is in contact with the surface. if the friction is not sufficient to make the body roll, it will also slide along its path. The friction which comes into play right now is the sliding friction. Static friction is the friction which comes into play, when the body is at rest and being acted by some force. It is always equal and opposite to the force applied. This will prevent the movement of the body to a certain limit.

Therefore, C is the correct answer.

Note
There is a different friction too known as static friction. This friction comes into play when the body is in motion. It also acts similar to static friction as it opposes the direction of motion. The value of kinetic friction will be less than the max value of static friction.