Question

Velocity time graph of a particle of mass 2 kg moving in a straight line is as shown in figure. Work done by all forces on the particle is 

(A) 400 J 

(B) – 400 J 

(C) – 200 J 

(D) 200 J

Answer 1

Correct option: (B) – 400 J

Explanation:

Workdone = Δ KE

= (1/2)m (V₂² – V₁²)

V₁ = Initial velocity = 20 m/s

V₂ = Final velocity = 0 m/s

WD = (1/2) × 2 (0 – 400)

= – 400 J