Wave Mechanics Question 522
Question: When the load on a wire is increasing slowly from 2 kg to 4 kg, the elongation increases from 0.6 mm to 1 mm. The work done during this extension of the wire is ( $ g=10m/s^{2} $ )
Options:
A) $ 9\times {{10}^{-3}}J $
B) $ 12\times {{10}^{-3}}J $
C) $ 14\times {{10}^{-3}}J $
D) $ 16\times {{10}^{-3}}J $
Show Answer
Answer:
Correct Answer: C
Solution:
[c] $ \Delta w=\frac{1}{2}[F _{2}{\ell _{2}}-F _{1}{\ell _{1}}] $
$ \begin{align} & =\frac{1}{2}[4\times 10\times 1\times {{10}^{-3}}-2\times 10\times 0.6\times {{10}^{-3}} \ & =14\times {{10}^{-3}}] \ $
BETA
