Vinyl Spinning Physics Problem

[Jacob Roman]

I already posted this in the math forum with no answer.

I'm making some turntables in 3D using DirectX8. I just figured out mathematically how to get the vinyls to spin exactly 33 1/3 rpm clockwise.

Now here's my problem. If I were to make it to where you click and hold the mouse down on the vinyl, which will cause it to stop, and after doing some scratching, I toss it by hand either forward or backward (Force). Tossing it forward will cause it to go faster, then cause it to slow down back to 33.5 rpm. Tossing it backward (counter clockwise) will cause it to play backwards briefly, some torque then come into play and pull it back forward slowly to 33.5 rpm. What physics formula do I need to pull this off? Thanx in advance.