Answer
$a).$ $56.3^{\circ}$ with respect to the horizontal x-axis.
$b).$ 18m/s
Work Step by Step
a). The angle of the rooftop is $\theta=tan^{-1}(\frac{15}{10})=56.3^{\circ}$ with respect to the horizontal (x-axis).
b). The speed $= \sqrt (15^{2}+10^{2})=18m/s$
