#### Answer

(a) The wave is traveling in the positive x-direction.
(b) $v = 2~m/s$

#### Work Step by Step

(a) At t = 0.01 s, the middle of the wave pulse is at the position x = -4 cm. At t = 0.04 s, the middle of the wave pulse is at the position x = 2 cm. Therefore, the wave is traveling in the positive x-direction.
(b) We can find the speed of the wave.
$v = \frac{\Delta x}{\Delta t}$
$v = \frac{2~cm-(-4~cm)}{0.04~s-0.01~s}$
$v = \frac{6~cm}{0.03~s}$
$v = 200~cm/s = 2~m/s$