question_answer

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:                                               [JEE ONLINE 10-04-2016]

A)             12000 J

B) 12000 J

C)             4500 J

D) 9300 J

Correct Answer: C

Solution :

[c]

\[\frac{8}{V}=\frac{10}{50}\]

\[V=40\,m/s\]

\[W=\frac{1}{2}\times 10\times (1600-2500)\]

\[=\frac{1}{2}\times 10\times (-900)\]

\[=-4500\,J\]