Originally Posted by Dan Ensor
Purple thingy's the hand, green thingy's the disc.
I wish I had noticed that earlier. I just want to point out now that the due to the disc's momentum being roughly linearly forwards and the hand being at 3 o'clock on the disc maximizes the amount of torque on the disc, as the force vector (from the disc's frame of reference) is now perpendicular to the edge of the disc (like a tangent) which creates the 90* angle needed to achieve sin(theta)=1, r from earlier is constant (in our model), which means that the force applied is dependent on the speed of the disc.
I'm doing this on the fly, and sorry for having two posts in a row.