A transverse sinusoidal wave is generted at one end of long, horizontal string by a bar that moves up and down through a distance of `1.00 cm`. The motion is continuous and is repreated regularly `120` times per second. The string has linear density `90 gm//m` and is kept under a tension of `900 N`. Find :
What is the maximum power (in watt) transferred along the string.

Options

A. zero
B. 3.77N
C. 37.7 N
D. 377 N

Answer

C

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.