Average velocity is the change in position over a time interval. Instantaneous velocity is the velocity at a specific moment in time, requiring calculus.

Uniform motion has constant velocity (zero acceleration). Non-uniform motion has changing velocity (non-zero acceleration).

Speed is the rate at which an object is moving. Velocity is the rate at which an object is moving in a specific direction.

Centripetal force is a real force that causes an object to move in a circular path, directed towards the center of the circle. Centrifugal force is a fictitious force that appears to act outward on an object moving in a circular path, only observed in a non-inertial (rotating) frame of reference.

It causes centripetal acceleration, resulting in uniform circular motion.

The centripetal acceleration is halved (a_c = v^2/r).

The center of mass shifts closer to the heavier mass.

The center of mass of the system accelerates.

Average velocity, $v_{avg}$, is calculated by dividing the change in position, $\Delta x$, by the change in time, $\Delta t$: $v_{avg} = \frac{\Delta x}{\Delta t}$.

Average acceleration, $a_{avg}$, is calculated by dividing the change in velocity, $\Delta v$, by the change in time, $\Delta t$: $a_{avg} = \frac{\Delta v}{\Delta t}$.

Centripetal acceleration, $a_c$, is calculated by dividing the square of the velocity, $v^2$, by the radius, $r$: $a_c = \frac{v^2}{r}$.

Centripetal force, $F_c$, is calculated by multiplying the mass, $m$, by the centripetal acceleration, $a_c$: $F_c = m a_c = \frac{mv^2}{r}$.