The coefficient of friction between an object and a surface,if we need to move an object of weight $150 \ N$ on a horizontal surface with a force of $75 \ N$,is

The maximum static frictional force is

$A$ block of mass $M$ rests on a rough horizontal table. $A$ steadily increasing horizontal force is applied such that the block starts to slide on the table without toppling. The force is continued even after sliding has started. Assume the coefficients of static and kinetic friction between the table and the block to be equal. The correct representation of the variation of the frictional force $f$,exerted by the table on the block with time $t$ is given by

If the normal force is doubled,the coefficient of friction is

$A$ force $F = mg$ is acting on a block of mass $m$ at an angle $\theta$ with the horizontal. The coefficient of friction between the block and the surface is $\mu$. The block can be pulled along the surface if:

$A$ horizontal force just sufficient to move a body of mass $4 \,kg$ lying on a rough horizontal surface is applied on it. The coefficients of static and kinetic friction are $0.8$ and $0.6$ respectively. If the force continues to act even after the body has started moving, the acceleration of the body is (take $g=10 \,ms^{-2}$). (in $\,ms^{-2}$)