Inertia Balance - Physics Demonstrations - Inertia Balance | Physics Undergraduate Labs

Purpose

A horizontally oscillating platform measures mass through inertia rather than gravity. Students observe that the oscillation period depends on the loaded mass, and that plotting $$T^2$$ vs. $$M$$ yields a straight line from which unknown masses can be determined -- a method that works even in zero gravity.

Inertia balance: a wooden base with two upright supports holding flexible metal blades that extend horizontally to a wooden oscillating platform, shown mid-oscillation as a blur. A calibrated mass set sits on the base beside it.

Figure 1: The inertia balance with calibrated mass set. The flexible metal blades provide the restoring force for horizontal oscillation.