$A$ body of mass $3 \, kg$ hits a wall at an angle of $60^\circ$ with the wall and returns at the same angle. The speed of the body is $10 \, m/s$ and the impact time is $0.2 \, s$. Calculate the force exerted on the wall.

$A$ man of mass $40\, kg$ is standing on a trolley $A$ of mass $140\, kg$. He pushes another trolley $B$ of mass $60\, kg$,so that they are set in motion. Then:

$A$ block $B$,lying on a table,has weight $w$. The coefficient of static friction between the block and the table is $\mu$. Assume that the cord between $B$ and the knot is horizontal. The maximum weight of the block $A$ for which the system will be stationary is

In the figure,a ball of mass $m$ is tied with two strings of equal length as shown. If the rod is rotated with angular velocity $\omega$,then

In a tug-of-war contest,two men pull on a horizontal rope from opposite sides. The winner will be the man who

$A$ $1 \,kg$ block situated on a rough incline is connected to a spring of negligible mass having spring constant $100 \,N \,m^{-1}$ as shown in the figure. The block is released from rest with the spring in the unstretched position. The block moves $10 \,cm$ down the incline before coming to rest. The coefficient of friction between the block and the incline is (Take $g=10 \,m \,s^{-2}$ and assume that the pulley is frictionless).