Question

A string of mass $2.5$kg is under a tension of 200 N. the length of the stretched string is 20 .m. if the transverse jerk is struck at one end of the string, the disturbance will reach the other end in.

• A. One second
• B. $0.5$ second
• C. 2 second
• D. data given is insufficient

Answer 1

Answer: (B)

$0.5$ second

Answer 2

Here, L = 20m, T = 200N, M = $2.5kg$

Mass per unit length,

$\mu = \frac{M}{L} = \frac{2.5kg}{20m} = 0.125kgm^{- 1}$

Velocity, $v = \sqrt{\frac{T}{\mu}} = \sqrt{\frac{200N}{0.125kgm^{- 1}}} = 40ms^{- 1}$

Time taken by disturbance to reach the other end,

$t = \frac{L}{v} = \frac{20m}{40ms^{- 1}} = 0.5s$