A) 16/25
B) 2/5
C) 3/5
D) 9/25
Correct Answer: B
Solution :
If ball falls from height \[{{h}_{1}}\] and bounces back up to height\[{{h}_{2}}\], then \[e=\sqrt{\frac{{{h}_{2}}}{{{h}_{1}}}}\] Similarly if the velocity of ball before and after collision are \[{{\nu }_{1}}\,\,and\,\,{{\nu }_{2}}\] respectively, then \[e=\frac{{{\nu }_{2}}}{{{\nu }_{1}}}\] So \[\frac{{{\nu }_{2}}}{{{\nu }_{1}}}=\sqrt{\frac{{{h}_{2}}}{{{h}_{1}}}}=\sqrt{\frac{1.8}{5}}=\sqrt{\frac{9}{25}}=\frac{3}{5}\] That is, fractional loss in velocity \[=\,\,\,1\,-\frac{{{\nu }_{2}}}{{{\nu }_{1}}}=1-\frac{3}{5}=\frac{2}{5}\]You need to login to perform this action.
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