A block of mass $2m$ is connected to another block of mass $m$ by a light inextensible string passing over a smooth pulley. The heavier block rests on a smooth horizontal table, while the lighter block hangs freely. The system is released from rest. If the heavier block is also connected to a light spring of spring constant $k$, initially unstretched, what is the maximum extension of the spring?

A cricket ball of mass 150 g collides straight with a bat with a velocity of 10 $\;{\rm{m}}{{\rm{s}}^{ - 1}}$. Batsman hits it straight back with a velocity of 20 $\;{\rm{m}}{{\rm{s}}^{ - 1}}$. If ball remains in contact with bat for 0. 1s, then average force exerted by the bat on the ball is

An automobile travelling with a speed of 60 km/h, can brake to stop within a distance of 20 m. If the car is going twice at fast,i.e. 120 km/h, the stopping distance will be

A lift is going up with uniform velocity. When brakes are applied, it slows down. A person in that lift experiences

In an ideal string tension at all points of all string will be

Two masses $\left( {M + m} \right)\,and\,\left( {M - m} \right)$ are attached to the ends of a light inextensible string and the string is made to pass over the surface of a smooth fixed pulley. When the masses are released from rest, the acceleration of the system is

A body of mass m collides against a wall with a velocity $v$ and rebounds with the same speed. Its change of momentum is

Inside a freely falling lift, a ball is released from rest. What will be the apparent weight of the ball?

Two masses $\left( {M + m} \right)\,and\,\left( {M - m} \right)$ are attached to the ends of a light inextensible string and the string is made to pass over the surface of a smooth fixed pulley. When the masses are released from rest, the acceleration of the system is

Which one of the following is not a force

In a one dimensional collision between two identical particles A and B, B is stationary and A has momentum p before impact. During impact B gives an impulse J to A. Then coefficient of restitution between the two is