Tilt angleSpin speed
THE PHYSICS
Why doesn’t it fall?
Gravity pulls down on the centre of mass, producing a torque about the pivot. Instead of simply tipping the fast-spinning wheel, that torque continually turns the direction of its angular momentum. The result is precession.
Ωp ≈ mgr / Iωidealised steady precession
A faster or heavier spinning wheel carries more angular momentum and resists rapid changes to its axis.
A mismatched initial condition produces a nodding motion superimposed on the precession.
Friction reduces spin and angular momentum. Precession accelerates until the gyroscope can no longer remain upright.