Question

A string of mass $3kg$ is under tension of $400N$. the length of the stretched string is $25cm$. If the transverse jerk is stuck at tone end of the string how long does the disturbance take to reach the other end?

• A. $0.043s$
• B. $4.335s$
• C. $0.005s$
• D. $0.034s$

Answer 1

The correct option is A

$0.043s$

Step 1. Given data

Mass of the string, $m=3kg$

Length of the stretched string, $L=25cm$

Tension in the string, $T=400N$

Step 2. Finding the time taken to reach at other end, $t$

Mass per unit length, $M=\frac{m}{L}$

$M=\frac{3}{25\times {10}^{-2}}$

Where, $L=25\times {10}^{-2}m$

$M=12kg{m}^{-1}$

By using the formula of velocity of wave, $v=\sqrt{\frac{T}{M}}$

$v=\sqrt{\frac{400}{12}}$

$v=5.77m{s}^{-1}$

By using the formula, $Time\left(t\right)=\frac{Dis\tan ce\left(L\right)}{Velocity\left(v\right)}$

$t=\frac{25\times {10}^{-2}}{5.77}$

$t=0.043s$

Hence, the correct option is $\left(A\right)$.