I would need an example or photo to give an answer.
It's c/f, in which c is the speed of light (300000 m/s)
First we find the angular acceleration
. The angular velocities are
and
The angular velocities and
are related as

Angle turned in 6.5 seconds is

The distance traveled by a point on the edge of the wheel is 
Break the circuit and apace a meter actually within the circuit.