Question

A certain 120 Hz wave on a string has an amplitude of 0.160 mm. The amount of energy exists in an 80 g length of the string is $58\times {10}^{-x}mJ$. Find x.

Answer 1

Energy carried by a wave of amplitude $A$, angular frequency $\omega$ and mass $m$=$\frac{1}{2}m{\omega }^2{A}^2$

$=\frac{1}{2}\times 0.08\times (2\pi \times 120{)}^2\times {0.00016}^2$

$=0.58\times {10}^{-3}J=0.58mJ$