A block of mass 2 kg is free to move along the x-axis it is at rset and from t=0 onwards it is subjected to a time dependent force F(t) in the x-direction The force F(t) varies with t as shown in the figure The kinetic energy of the block after `4.5` seconds, is:

Options

A. `4.50 J`
B. `7.50 J`
C. `5.06 J`
D. `14.06 J`

Answer

C

Explanation

Change in momentum = Area under F-t graph
`=1/2xx4xx3-1/2xx1.5xx2=4.5 kg m//s`
:. K.E. `=p^(2)/(2m)=(4.5)^(2)/(2xx2)=5.06 J`