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Question:

Velocity-time graph for a body of mass 10 kg is shown in figure. Work-done on the body in first two seconds of the motion is :

J

J

2000 J

12000 J

Solution:

Velocity is changing as per, v = 20t + 50
At t = 2, v = 40
ΔK.E = W.D = 1/2(40² - 0²) × 10 = 8000 J