A body of mass` 5 kg` is moving with a momentum of `10 kg m//s`. A force of `0.2 N` acts on it in the direction of motion of the body for `10 sec.` The increase in its kinetic energy.

Options

A. 3.8 joule
B. 2.8 joule
C. 3.2 joule
D. 4.4 joule

Answer

D

Explanation

When the ball falls on the spring, the spring is compressed.
`therefore` The work done = P.E. stored in the spring `=(1)/(2)kd^(2)`
and the P.E. lost by the ball, when it falls through a distance `(h+d)=mg(h+d)`
`therefore` The net work done in this process
`=mg(h+d)-(1)/(2)kd^(2)`