# What causes a gyroscope to eventually rotate/fall over?

Hey so I've just learned about angular velocity and momentum and how torque changes it.

Looking at a wheel spinning around an axis, with one end being held up by a rope, what causes the wheel to rotate downwards over time, and eventually fall?

-
I didn't saw it rotating backwards, the only thing which i saw was that the wheel stops after some time, that can be easily attributed to the friction the ball bearing offers.... –  Vineet Menon Sep 25 '11 at 12:19