A $10-$m$-$long glider with a mass of $680kg{g}^n($including the passengers$)$ is gliding horizontally through the air at $30\frac{m}{s}$ when a $60$ kg skydiver drops out by releasing his grip on the glider. What is the glider's velocity just after the skydiver lets go$?($Hint: Remember that separate conservation of momentum equations are written for each direction, $x,y,$ and z $.)$