A transverse harmonic wave on a string is given by y (x, t) = 5sin...

The general equation for a wave can be written as $y = Asin\left(\omegat + kx\right)$. Comparing it with the given equation, $y = 5\sin \left(6t + 0 . 003x\right)$,

$\omega = 6rad{s}^{- 1}$, $k = 0 . 003{cm}^{- 1}$

Using the equation, $v = \dfrac{\omega}{k}$

$v = \dfrac{6}{0 . 003 \times {10}^{2}} = 20m{s}^{- 1}$