Moments – principle of moments and couples

PhysicsForces & DynamicsAges 15–16

A virtual lab with a rod pivoted at its centre and equally spaced holes: drag masses onto holes on either side and the rod tilts towards the side with the larger moment, settling horizontal only when M₁ = F₁·d₁ equals M₂ = F₂·d₂. A table records each trial so the principle of moments can be checked. Couple mode shows that two equal and opposite forces only make the rod rotate, with M = F·d.