Acceleration, Mass - Physics Demonstrations - Acceleration, Mass | Physics Undergraduate Labs

Use proper lifting technique with the heavy rock. Do not attempt to lift it repeatedly — demonstrate the effort once, then set it down.

Purpose

Demonstrates that acceleration is proportional to mass ( $$F = ma$$ ). Contrasting the effort to lift a heavy rock versus a realistic-looking styrofoam boulder gives students a visceral sense that mass measures resistance to acceleration.

Large styrofoam boulder with realistic rough, weathered surface on the forks of a yellow hydraulic forklift in a classroom

Close-up of the styrofoam boulder showing convincingly realistic rough, porous rock texture with varied coloration

Figure 1: The styrofoam boulder on its forklift. Despite looking like it weighs hundreds of pounds, it can be flung easily — the forklift sells the illusion.

Figure 2: Close-up showing the realistic surface texture. The boulder is styrofoam — handle carefully to avoid damage.

Safety Warnings

Warning: Lifting Hazard

Purpose