The maximum static frictional force is

A body of mass M is kept on a rough horizontal surface (friction coefficient $\mu $). A person is trying to pull the body by applying a horizontal force but the body is not moving. The force by the surface on the body is $F$, where

The force required just to move a body up an inclined plane is double the force required just to prevent the body from sliding down. If $\mu $ is the coefficient of friction, the inclination of plane to the horizontal is

A block of mass $0.1 \,kg$ is held against a wall by applying a horizontal force of $5\, N$ on the block. If the coefficient of friction between the block and the wall is $0.5$, the magnitude of the frictional force acting on the block is ........ $N$

A pen of mass $m$ is lying on a piece of paper of mass $M$ placed on a rough table. If the coefficients of friction between the pen and paper and the paper and the table are $\mu_1$ and $\mu_2$, respectively. Then, the minimum horizontal force with which the paper has to be pulled for the pen to start slipping is given by

A block weighs $W$ is held against a vertical wall by applying a horizontal force $F$. The minimum value of $F$ needed to hold the block is