A) \[(2\sqrt{2}-1)m/s\]
B) \[(2\sqrt{2}+1)m/s\]
C) \[4.5\,m/s\]
D) none of these
Correct Answer: B
Solution :
Man possesses kinetic energy, because of its velocity (v). When m is mass of man, then \[K=\frac{1}{2}m{{v}^{2}}\] Given, \[{{v}_{1}}=v,\,{{m}_{1}}={{m}_{2}}=m,\,{{v}_{2}}=(v+2)\,m/s,\] \[{{K}_{2}}=2{{K}_{1}}\] \[\therefore \] \[\frac{{{K}_{1}}}{{{K}_{2}}}=\frac{{{v}_{1}}^{2}}{{{v}_{2}}^{2}}\] \[\frac{{{K}_{1}}}{2{{K}_{1}}}=\frac{{{v}^{2}}}{{{(v+2)}^{2}}}\] \[\Rightarrow \] \[{{v}^{2}}-4v-4\] \[\Rightarrow \] \[{{v}_{1}}=\frac{4+\sqrt{16+16}}{2}=\frac{4+\sqrt{32}}{2}\] \[=2(\sqrt{2}+1)\,m/s\]
You need to login to perform this action.
You will be redirected in
3 sec
