Spinning Ring - Physics Demonstrations - Spinning Ring | Physics Undergraduate Labs

Keep students clear of the spinning frame. Inspect the suspension string for wear before each use.

Purpose

A suspended ring hangs vertically at rest but reorients to spin horizontally as rotation speed increases. Demonstrates that rotating bodies align with the axis of maximum moment of inertia, minimizing $$E = L^2/2I$$ for a given angular momentum.

Centrifugal machine with a triangular black metal frame on a base; a small brass ring hangs vertically from a string at the apex; a large hand-crank wheel with wooden handle is visible at right

The centrifugal machine spinning rapidly with the triangular frame blurred by motion; the brass ring is visible near the base having risen from its hanging position; a hand turns the crank at right

Figure 1: Centrifugal machine at rest with the brass ring hanging vertically from the apex of the triangular frame.

Figure 2: Apparatus spinning at high speed. The ring has risen toward horizontal, aligning with the axis of maximum moment of inertia.

Centrifugal Machine

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Safety Warnings

Warning: Rotating Equipment Precaution

Purpose