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 :

A) 12000 J                                    

B) 12000 J                

C) 4500 J                      

D) 9300 J

Correct Answer: C

Solution :

             \[\frac{8}{V}=\frac{10}{50}\] \[V=40\,m/s\] \[W=\frac{1}{2}\times 10\times (1600-2500)\] \[=\frac{1}{2}\times 10\times (-900)\] \[=-4500\,J\]