Angular Position and Displacement

When an object rotates about a fixed point, we describe its angular position $\theta$ as the angle through which it has rotated from a reference direction.

While angles can be measured in degrees, physics will often use radians. A radian is the angle swept out when the arc length equals the radius.

Since a complete circle has circumference $2\pi r$, there are $2\pi$ radians in one full revolution.

This gives us $2\pi \text{ rad} = 360^\circ$, or $1 \text{ rad} \approx 57.3^\circ$.