Work Energy And Power Ques 17
17. When a long spring is stretched by $2$ $ cm$, its potential energy is $U$. If the spring is stretched by $10$ $ cm$, the potential energy stored in it will be
[2003]
(a) $25 $ $U$
(b) $U / 5$
(c) $5 $ $U$
(d) $10 $ $U$
Show Answer
Answer:
Correct Answer: 17.(a)
Solution:
- (a) If $k$ be the spring constant, then
$U=\frac{1}{2} \times k \times(2)^{2}=2k$
$U _{\text{final }}=\frac{1}{2} \times k \times(10)^{2}=50k$
$\Rightarrow \frac{U}{U _{\text{final }}}=\frac{2 k}{50 k}=\frac{1}{25}$
$\Rightarrow U _{\text{final }}=25\ U$
BETA
