A) 19%
B) 26%
C) 38%
D) 57%
Correct Answer: C
Solution :
\[{{E}_{1}}=\frac{1}{2}mv_{2}^{2}+mgh=72\,\,m+12\,\,mg\] \[{{E}_{2}}=mgh=12\,mg\] \[{{E}_{1}}-{{E}_{2}}=72\,mg\] Percentage saving \[=\left( \frac{{{E}_{1}}-{{E}_{2}}}{{{E}_{1}}} \right)\times 100\] \[=\frac{72\,m\times 9.81\times 100}{(72\,m+12\times 9.81\times m)}\] = 38%You need to login to perform this action.
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