Answer
(a) $k = 3.1~rad/m$
(b) $v = 9.6~m/s$
Work Step by Step
(a) We can find the wave number as:
$k = \frac{2\pi}{\lambda}$
$k = \frac{2\pi~rad}{2.0~m}$
$k = 3.1~rad/m$
(b) We can find the frequency as:
$f = \frac{\omega}{2\pi}$
$f = \frac{30~rad/s}{2\pi}$
$f = 4.8~Hz$
We can find the wave speed as:
$v = \lambda~f$
$v = (2.0~m)(4.8~Hz)$
$v = 9.6~m/s$