Question. A light inextensible string that goes over a smooth fixed pulley as shown in the figure connects two blocks of masses 0.36kg and 0.72kg. Taking g=10 m/s2, find the work done (in joules) by the string on the block of mass 0.36 kg during the first second after the system is released from rest.
Example: A batsman hits a ball of mass m moving with an initial velocity of u. After the impact, the direction of motion of the ball reverses and velocity becomes v. Find the work done by the batsman on the ball. Solution: Change in kinetic energy , ΔK=21mv2−21mu2 By work-energy theorem, work done by batsman is, W=ΔK=21mv2−21mu2