Lately i have been watching the MIT Physics Lectures from Dr. Walter Lewin. I find his passion while teaching very fascinating and inspiring. Any way, in the end of the lecture about Torque he showed a weird phenomenon which ,he admitted, baffled himself for a while.
He place a piece of plastic onto the projector's glass surface and he spined it counter clockwise and the result was as expected. The body spined till the friction (however small) stopped it. However when he spinned it clockwise the friction brought it to a halt and then its direction of rotation is reversed.
For your convenience if you haven't seen the lecture. Click here (and go to 46th minute)
I asked my physics teacher and he assumed that there is either some kind of liquid in the plastic and the body when spinned changes it's moment of inertia and that's how the motion is affected or there is some monkey business. However that doesn't seem likely to me.
So my question is how is this motion possible? And could you share with me the mathematical approach of the motion?