A transverse sinusoidal wave is generated at one end of a long horizontal string by a bar is continuous and is repeated regularly 120 times per second. The string has linear density of 117g/m. the other end of the string is attached to a mass 4.68kg. the string passes over a smooth pulley and the mass attached to the other end of the string hangs freely under gravity.
The maximum power transferred along the string is:

Options

A. 3.845 kW
B. 34.85 kW
C. `348.5 kW//d`
D. None of these

Answer

B

Explanation

Tension in the string should be

T = mg
T = 46.8 N
Speed of wave should be
`v = sqrt((t)/(mu)) = sqrt((46.8)/(0.117)) = 20ms^(-1)`
Power of wave on string is given as
`P = (1)/(2)A^(2)omega^(2)muv`
= `(1)/(2) xx (1.12 xx 10^(-2))^(2) xx(2pi xx 120)^(2) xx 0.117 xx 10^(-3) xx20 `
0.0834 W.