Work Energy And Power Question 238
Question: A ball dropped from a height of 2m reaches to a height of 1.5m before hitting the ground. Then the percentage of potential energy lost is
Options:
A) 25
B) 30
C) 50
D) 100
Show Answer
Answer:
Correct Answer: A
Solution:
[a] $ {U_1}=mgh_1andU_2=mgh_2 $
$ % energy lost = \frac{U_1-U_2}{U_1}\times 100 $
$ =\frac{mgh_1-mgh_2}{mgh_1}\times 100=( \frac{h_1-h_2}{h_1} )\times 100 $
$ =\frac{2-1.5}{2}\times 100=25% $
