The velocity-time graph of a particle moving in a straight line is shown in figure. The mass of the particle is `2kg`. Work done by all the forces acting on the particle in time interval between `t=0` to `t=10s` is

Options

A. (a) `300J`
B. (b) `-300J`
C. (c) `400J`
D. (d) `-400J`

Answer

A

Explanation

From work-energy theorem,
`W=DeltaKE=K_f-K_i=1/2m(v_f^2-v_i^2)`
`=1/2xx2[(-20)^2-(10)^2]=300J`