A block of mass M is hanging over a smooth and light pulley through a light string. The other end of the strinig is pulled by a constant force F. The kinetic energy of the block increases by 20J n 1s.
A. the tension in the string is Mg
B. The tension is the string is F
C. The work done by the tension on the block is 20 J in the above 1s.
D. the work done by the force of gravity is -20J in the above 1s.