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 $[\mu < 1]$

A $1.0 kg$ block of wood sits on top of an identical block of wood, which sits on top of a flat level table made of plastic. The coefficient of static friction between the wood surfaces is $\mu_1$, and the coefficient of static friction between the wood and plastic is $\mu_2$. Ahorizontal force $F$ is applied to the top block only, and this force is increased until the top block starts to move. The bottom block will move with the top block if and only if

A uniform chain of length $L$ changes partly from a table which is kept in equilibrium by friction. The maximum length that can withstand without slipping is $l$, then coefficient of friction between the table and the chain is

A horizontal force $12 \,N$ pushes a block weighing $1/2\, kg$ against a vertical wall.  The  coefficient of static friction between the wall and the block is $0.5$ and the coefficient of  kinetic friction is $0.35.$ Assuming that the block is not moving  initially. Which one of the following choices is correct (Take $g = 10 \,m/s^2$)

A force $\vec{F}=\hat{i}+4 \hat{j}$ acts on the block shown. The force of friction acting on the block is

A chain of length $L$ rests on a rough table. If $\mu $ be the coefficient of friction, the maximum friction of the chain that can hang over the table will be