## College Physics (4th Edition)

We can write an expression for the speed of a wave along a string: $v = \sqrt{\frac{T}{m/L}}$, where $m$ is the mass of the string The copper coil increases the mass of the string which decreases the speed of the wave along the string. If the wave speed decreases, then the frequency decreases. The purpose of the copper coil is to decrease the wave speed, which in turn decreases the frequency of the musical tone that is produced.