Q: A 4 kg block is suspended from the ceiling of an elevator through a string having a linear mass density of 19.2 × 10-3 kg m-1. Find the speed with which a wave pulse can travel on the string if the elevator accelerates up at 3 ms-2? (g = 10 ms-2)
Sol: $\large v = \sqrt{\frac{T}{\mu}}$
$\large v = \sqrt{\frac{M(g+a)}{\mu}}$
$\large v = \sqrt{\frac{4(10 + 2)}{19.2 \times 10^{-3}}}$
v = 50 m/s