List of top Physics Questions on Friction asked in IIT JAM BT

Consider a block of mass \(m\) hanging using a string and pulley arrangement, as shown in the figure. The weight \(mg\) and tension \(T\) are working on the block in such a way that the block is not moving and the string is parallel to the perfectly vertical wall. If the block is just in contact but not attached/fixed with the wall and the coefficient of static friction is \(\mu\), then the static frictional force acting on the block is

A box of mass 20 𝑘𝑔 is pulled at constant speed across a floor by a rope. The rope makes an angle of 45° with the horizontal. Assuming that friction is negligible, the work done in pulling the box by a distance of 20 𝑚 is _____ 𝐽 (rounded off to the nearest integer). (Use $𝑔 = 9.8 𝑚𝑠^{−2}$)