A string of mass 2.5 kg is under tension of 200 N. The length of the stretched string is 20.0 m. If the…

A string of mass 2.5 kg is under tension of 200 N. The length of the stretched string is 20.0 m. If the transverse jerk is struck at one end of the string, the disturbance will reach the other end in [NCERT Exemplar] Diagram showing a horizontal string of length 20 m fixed to a wall under tension T = 200 N.
  1. 1 s
  2. 0.5 s
  3. 2 s
  4. data given is insufficient

Solution

Mass, $m = 2.5\text{ kg}$ $\mu = \text{mass per unit length}$ $= \frac{m}{l} = \frac{2.5\text{ kg}}{20} = \frac{1.25}{10} = 0.125\text{ kg m}^{-1}$ Speed, $v = \sqrt{\frac{T}{\mu}} = \sqrt{\frac{200}{0.125}}$ (Speed of transverse waves in any string) $l = v \times t \Rightarrow 20 = \sqrt{\frac{200}{0.125}} \times t$

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