A) \[\sqrt{2}\,\,m/s\]
B) \[(\sqrt{2}-1)\,\,m/s\]
C) \[\frac{1}{(\sqrt{2}-1)}\,\,m/s\]
D) \[\frac{1}{\sqrt{2}}\,\,m/s\]
Correct Answer: C
Solution :
Suppose mass and speed of man is \[M\] and \[V\] respectively. Suppose the speed of the boy is \[v\] Then. \[\frac{1}{2}M{{V}^{2}}=\frac{1}{2}\left[ \frac{1}{2}\cdot \left( \frac{M}{2}\cdot \right){{v}^{2}} \right]\] ? (1) \[\frac{1}{2}M{{(V+1)}^{2}}=\frac{1}{2}\left( \frac{M}{V} \right){{v}^{2}}\] ... (2) Dividing equation (1) by equation (2) we obtain \[\frac{{{V}^{2}}}{{{(V+1)}^{2}}}=\frac{1}{2}\] or \[\frac{V}{(V+1)}=\frac{1}{\sqrt{2}}\]
You need to login to perform this action.
You will be redirected in
3 sec
