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. 2.8 Joule
B. 3.2 Joule
C. 3.8 Joule
D. 4.4 Joule

Answer

D

Explanation

Change in momentum = Force `xx` time
`P_(2)-P_(1)=F xx t = 0.2xx10=2`
`rArr P_(2)=2+P_(1)=2+10=12` kg-m/s
Increase in K.E. `= (1)/(2m)(P_(2)^(2)-P_(1)^(2))=(1)/(2xx5)[(12)^(2)-(10)^(2)]`
`= (44)/(10)=4.4 J`