You are designing a demo that is meant to illustrate Faraday’s Law. It consists of a disk with a known mass and radius ($M,R$) that has a total charge $Q$ stuck uniformly to the edge of it. The disk is the same radius as a long solenoid positioned just below it ($n$ rotations per length). The solenoid is connected to a current supply that provides a very slowly oscillating current (at a frequency of $\omega_0 \ll c/R$).
Find the response of the disk, i.e., how it rotates.
By selecting appropraite parameters (make sure to justfiy them!), design the demo to have a reasonable rotation rate that kids could observe with the naked eye.