Answer:
Part a)
[tex]v = \sqrt{xg + \frac{MLg}{m}}[/tex]
Part b)
t = 12 s
Explanation:
Part a)
Tension in the rope at a distance x from the lower end is given as
[tex]T = \frac{m}{L}xg + Mg[/tex]
so the speed of the wave at that position is given as
[tex]v = \sqrt{\frac{T}{\mu}}[/tex]
here we know that
[tex]\mu = \frac{m}{L}[/tex]
now we have
[tex]v = \sqrt{\frac{ \frac{m}{L}xg + Mg}{m/L}[/tex]
[tex]v = \sqrt{xg + \frac{MLg}{m}}[/tex]
Part b)
time taken by the wave to reach the top is given as
[tex]t = \int \frac{dx}{\sqrt{xg + \frac{MLg}{m}}}[/tex]
[tex]t = \frac{1}{g}(2\sqrt{xg + \frac{MLg}{m}})[/tex]
[tex]t = \frac{2}{9.8}(\sqrt{(39.2\times 9.8) + \frac{8(39.2)(9.8)}{1}})[/tex]
[tex]t = 12 s[/tex]