The speed of an object and the direction in which it moves constitute a vector quantity known as the velocity. An ostrich is running at a speed of 17.0 $\mathrm{m} / \mathrm{s}$ in a direction of $68.0^{\circ}$ north of west. What is the magnitude of the ostrich's velocity component that is directed (a) due north and $(\mathrm{b})$ due west?