The radius of the circle, the period of revolution, initial position and direction of revolution are indicated in the figure.

The $y$-projection of the radius vector of rotating particle $P$ will be:
1. $y(t)=3 \cos \left(\dfrac{\pi \mathrm{t}}{2}\right)$, where $y$ in m
2. $y(t)=-3 \cos 2 \pi t$ , where $y$ in m
3. $y(t)=4 \sin \left(\dfrac{\pi t}{2}\right)$, where $y$ in m
4. $y(t)=3 \cos \left(\dfrac{3 \pi \mathrm{t}}{2}\right)$,  where $y$ in m