## University Physics with Modern Physics (14th Edition)

If the angular velocity is constant, then for a point on the rim, the linear velocity must also be constant. Then the tangential acceleration is zero. The radial acceleration is equal to $\omega^2~r$, where $r$ is the radius of the flywheel. Since $\omega$ and $r$ are constant, then the radial acceleration is also constant in magnitude. Since the radial acceleration always points toward the center of the circle, the direction of the radial acceleration for a point on the rim is always changing as the flywheel rotates.
If the angular velocity is constant, then for a point on the rim, the linear velocity must also be constant. Then the tangential acceleration is zero. The radial acceleration is equal to $\omega^2~r$, where $r$ is the radius of the flywheel. Since $\omega$ and $r$ are constant, then the radial acceleration is also constant in magnitude. Since the radial acceleration always points toward the center of the circle, the direction of the radial acceleration for a point on the rim is always changing as the flywheel rotates.