question_answer

A man is 45 m behind the bus, when the bus start accelerating from rest with acceleration \[2.5\text{ }m/{{s}^{2}}.\] With what minimum velocity should the man start running to catch the bus ?

A)  12 m/s                

B)  14 m/s

C)  15 m/s                                

D)  16 m/s

Correct Answer: C

Solution :

                 In order that the man catches the bus, let his minimum velocity be v, then from equation of motion \[{{v}^{2}}={{u}^{2}}+2as\] We have,\[u=0\](initial velocity),\[a=2.5\text{ }m/{{s}^{2}},\] \[s=45\text{ }m\] \[\therefore \]  \[{{v}^{2}}=2\times 2.5\times 45\] \[\Rightarrow \]               \[v=\sqrt{225}=15\text{ }m/s\]