question_answer

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

A)  \[12\text{ }m/s\]     

B)   \[14\text{ }m/s\]

C)  \[15\text{ }m/s\]       

D)  \[16\text{ }m/s\]

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), \[a=2.5\text{ }m/{{s}^{2}},\] \[s=45\,\,m\] \[\therefore \] \[{{v}^{2}}=2\times 2.5\times 45\] \[\Rightarrow \] \[v=\sqrt{225}=15m/s\]