Question

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

• A. $-9300J$
• B. $12000J$
• C. $-4500J$
• D. $-12000J$

Answer 1

Answer: (C)

$-4500J$

Velocity is changing as per, $v=-5t+50$
$v_{t=2}=40$
$\Delta K.E=W.D=\frac{1}{2}({40}^2-{50}^2)\times 10$
$=-4500J$