WBJEE 2013 Physics Solved Paper

A block of mass m (= 0.1 kg) is hanging over a frictionless light fixed pulley by an inextensible string of negligible mass. The other end of the string is pulled by a constant force F in the verticaly downward direction. The linear momentum of the blockincrease by 2 kg ms–1 in 1 s after the block starts from rest. Then, (given g = 10 ms–2)