The radial velocity of a particle moving in a circle is the component of its velocity vector that is directed along the radius of the circle. It represents how fast the particle is moving towards or away from the center of the circle.
For a particle moving at a constant speed in a perfect circle, the radial velocity is always perpendicular to the tangent of the circle at any given point. At any instant, the radial velocity vector points directly towards or away from the center of the circle. The magnitude of the radial velocity is equal to the speed of the particle.
If we consider the angular velocity of the particle, which is the rate at which it sweeps out angle along the circle, the radial velocity can be calculated using the following formula:
Radial velocity = (Angular velocity) × (Radius of the circle)
The direction of the radial velocity depends on the direction of the particle's motion. If the particle is moving clockwise, the radial velocity is directed towards the center of the circle. Conversely, if the particle is moving counterclockwise, the radial velocity is directed away from the center.
It's important to note that the radial velocity is different from the tangential velocity, which represents the component of the particle's velocity that is tangent to the circle and determines how fast the particle is moving around the circle.