Chapter$-15$: A uniform string has a mass of $0\mathrm{.}2$ kg $,$ and total length $L=4m,$ and is shown in Figure$-6.$ The string passes over a frictionless pulley and supports an object with $M=10kg$ object. Assume that a pulse is excited on the string. Find the speed, v$,$ of a pulse travelling along this string. Show all work.

Figure$-6$: Diagram for problem #$9.$