A block of mass m = 10 kg is hanging over a frictionless light fixed pulley by an inextensible light rope. Initially the block is held at rest. The other end of the rope is now pulled by a constant force F in the vertically downward direction. The linear momentum of the block is seen to increase by 2 kgm/s in 1 s (in the first second). Therefore,

A

the tension in the rope is F

B

the tension in the rope is 3 N

C

the work done by the tension on the block, in first second, is 19.8 J

D

the work done against the force of gravity, in first second, is 9.8 J