Objective
Spin a flywheel and see Newton's second law for rotation: torque changes angular velocity, and the moment of inertia resists that change.
The idea
Push torque on the disc and watch it spin up. Change its radius or mass and feel how much harder it becomes to spin - that is moment of inertia, rotation's answer to mass.
Try this
- 1Crank the torque up and down while the disc is spinning.
- 2Grow the radius with the same torque and watch the spin slow.
- 3Pump up the mass and see the wheel become sluggish.
- 4Pause it, then re-apply torque to watch it re-accelerate from rest.
Watch for
- alpha = torque / moment of inertia: more torque, faster spin-up.
- I grows with mass and with the square of radius.
- Angular velocity keeps climbing while torque acts (rotation's v = at).
- Rotational kinetic energy grows with omega squared.