Question

A uniform string of length 20m is suspended from a rigid support. A short wave pulse is introduced at its lowest end. It starts moving up the string. The time taken to reach the support is: (take $g=10m{S}^{-2}$

• A. 2s
• B.
• C.
• D.

Answer 1

The correct option is B

$v=\sqrt{\frac{T}{\mu }}$
$\frac{dx}{dt}=\sqrt{\frac{uxg}{\mu }}$
$\underset{0}{\overset{L}{\int }}\frac{dx}{\sqrt{xg}}={\int }_0^{l}dt$
$\Rightarrow t=2\sqrt{2}s$