Question

A wave pulse is travelling on a string of linear mass density $6.4\times 10^{-3}kg{m}^{-1}$ under a load of $80kgf$ . Calculate the time taken by the pulse to traverse the string, if its length is $0.7m$

• A. $2\times 10^{-3}s$
• B. $3\times 10^{-3}s$
• C. $4\times 10^{-2}s$
• D. $5\times 10^{2}s$

Answer 1

Answer: (A)

Here, $\text{T = 80}$ kgf = $\text{= 80 }\times \text{ 9}\text{.8 }$ N ;
$m=6.4\times 10^{-3}$ kg m^-1
$Now,\upsilon =\sqrt{\frac{\text{T}}{\text{m}}}=\sqrt{\frac{80\times 9\cdot 8}{6\cdot 4\times 10^{-3}}}=350\text{m }{\text{s}}^{-1}$
Therefore, time taken by the wave pulse to traverse 0.7 m length of the string,
$t=\frac{l}{\upsilon }=\frac{\text{0}\text{.}7}{350}=2\times 10^{-3}$ s