A 4.0 kg block is suspended from the ceiling of an elevator by a...

The effective acceleration of the block in the elevator accelerating upward is given by:

$g_{\text{eff}} = g + a = 10 + 2.0 = 12.0 \text{ m s}^{-2}$

The tension in the string is equal to the apparent weight of the suspended block:

$T = M g_{\text{eff}} = 4.0 \times 12.0 = 48 \text{ N}$

The speed of a transverse wave pulse on a string is given by the formula:

$v = \sqrt{\dfrac{T}{\mu}}$

Substituting the given values:

$v = \sqrt{\dfrac{48}{19.2 \times 10^{-3}}}$

$v = \sqrt{\dfrac{48000}{19.2}} = \sqrt{2500}$

$v = 50 \text{ m s}^{-1}$