A uniform rod of length L and mass m is placed on rough horizontal surface.If coefficient of friction is $\mu =kx$,where k is constant and $\mu$ exist for $0\le x\le L$ (i.e for $x>L$ friction is zero.). If rod moves towards the right, magnitude of work done by friction is:

Q. A uniform rod of length L and mass m is placed on rough horizontal surface.If coefficient of friction is $\mu =kx$,where k is constant and $\mu$ exist for $0\le x\le L$ (i.e for $x>L$ friction is zero.). If rod moves towards the right, magnitude of work done by friction is:

Q. A cubical wooden box of side $L$ is placed on a horizontal rough surface and the coefficient of static friction between them is $\mu$. Another cubical box of same wood but of length $2L$ is placed on the same surface. Then the coefficient of static friction is

Q. A block of mass $m$ is pulled by a constant power $P$ placed on a rough horizontal plane. The friction coefficient between the block and surface is $\mu .$ Find the maximum velocity of the block.

Q. One fourth length of a uniform rod is placed on a rough horizontal surface and rod starts rotating about the edge. At an angle $\theta$ between the rod and the horizontal, rod begins to slide on the edge. If coefficient of friction between rod and surface is $\mu$ and 13 tan $\theta =x\left(\mu \right).$ Find x. (Take g$=10m/s^2)$

Q. A uniform rod $ABC$ of mass $M$ is placed vertically on a rough horizontal surface. The coefficient of kinetic friction between the rod and the surface is $\mu$. A force $F(>\mu mg)$ is applied on the rod at point $B$ at distance $l/3$ below centre of the rod as shown in figure. The initial acceleration of point $A$ is