A block of $7\,kg$ is placed on a rough horizontal surface and is pulled through a variable force $F$ (in $N$ ) $= 5\,t$ , where $'t'$ is time in second, at an angle of $37^o$ with the horizontal as shown in figure. The coefficient of static friction of the block with the surface is one. If the force starts acting at $t = 0\,s$ . Find the time at which the block starts to slide ......... $\sec$ (Take $g = 10\,m/s^2$ )

A truck starting from rest moves with an acceleration of $5 m/s^2$ for $1 sec$ and then moves with constant velocity. The velocity $w.r.t$ ground $v/s$ time graph for block in truck is ( Assume that block does not fall off the truck)

A block of mass $M$ is held against a rough vertical well by pressing it with a finger. If the coefficient of friction between the block and the wall is $\mu $ and acceleration due to gravity is $g$, calculate the minimum force required to be applied by the finger to hold the block against the wall.

In the given figure the acceleration of $M$ is $(g = 10 \,ms^{-2})$

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

The limiting friction between two bodies in contact is independent of