question_answer 36)

                  A string of mass 2.5 kg is under a 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                 (a) one second                 (b) 0.5 second                 (c) 2 seconds                 (d) data given is insufficient.

Answer:

                  (b) \[\upsilon \,=\,\sqrt{\frac{T}{\mu }}\,=\,\sqrt{\frac{200}{2.5/20}}=40\,m{{s}^{-1}}\]                 \[t=\,\frac{\text{Distance}}{\upsilon }\,=\,\frac{20}{40}\,=\,0.5\,s.\]