Answer
$v=\sqrt{c^2k^2+b^2}$
$a=ck^2$
Work Step by Step
$x=c\sin kt$
$\dot{x}=ck\cos kt$
$\ddot{x}=-ck^2\sin kt$
$y=c\cos kt$
$\dot{y}=-ck\sin kt$
$\ddot{y}=-ck^2\cos kt$
$z=h-bt$
$\dot{z}=-b$
$\ddot{z}=0$
$v=\sqrt{(ck\cos kt)^2+(-ck \sin kt)^2+(-b)^2}=\sqrt{c^2k^2+b^2}$
$a=\sqrt{(-ck^2\sin kt)^2+(-ck^2\cos kt)^2+0}=ck^2$