The graph between the resistive force `F` acting on a body and the distance covered by the body is shown in the figure. The mass of the body is `25 kg` and initial velocity is `2 m//s`. When the distance covered by the body is `4m`, its kinetic energy would be

Options

A. 50 J
B. 40 J
C. 20 J
D. 10 J

Answer

D

Explanation

`(KE)_(i) =1/2 mv^2 =1/2xx25 xx(2)^2 =50 J`
Work done (W) = Area under F - S graph
`=1/2 xx 20 xx 4 = 40 J`
From Work energy theorem `DeltaKE =W`
`implies 50 -(KE)_f = 40 implies (KE)_f = 10 J`