The speed of transverse waves

On a stretched string, a disturbance travels as a transverse wave. The restoring force that pulls a displaced bit of string back toward its rest line is supplied by the string's own tension T, and the relevant inertial property is the string's linear mass density m -- its mass per unit length, $m=M/L$ for a string of total mass M and length L. Combining these gives the speed of a transverse wave on a stretched string,

$v=\sqrt{\dfrac{T}{m}}$ …