Answer
(a) increase
(b) $v=\sqrt{yg}$
Work Step by Step
(a) The speed of the wave increases with increasing tension and as the tension in the rope is highest at the top of the rope, the speed of the wave increases as it moves up the rope.
(b) We know that
$v=\sqrt{\frac{F}{\mu}}$
$\implies v=\sqrt{\frac{\mu yg}{\mu}}$
$v=\sqrt{yg}$
