Lever Classes

This interactive simulator explores Lever Classes in Classical Mechanics. 1st / 2nd / 3rd class: arms, τ about fulcrum, MA vs Torque & Balance. Use the controls to change the scenario; watch the visualization and any graphs or readouts to connect the model with lectures, labs, and homework.

Who it's for: Suited to beginners and first exposure to the topic. Typical context: Classical Mechanics.

Key terms

  • lever
  • classes
  • lever classes
  • mechanics
  • classical

How it works

Levers are classified by where the fulcrum sits relative to the load and the effort. This lab fixes a horizontal rigid bar, takes torques about the fulcrum, and uses the usual sign: counterclockwise positive in the view. Class 1 (seesaw): both weights pull down on opposite sides of the pivot. Class 2 (wheelbarrow model): the load hangs between pivot and the point where you apply an upward effort; the ideal mechanical advantage d_eff/d_load can exceed 1. Class 3 (tongs / forearm model): you apply effort between pivot and load; equilibrium requires |F_eff| > W_load, trading force for motion range. Compare with Torque & Balance, which is a general beam with a movable pivot but not this ABC classification.

Key equations

Σ τ = 0 at equilibrium · τ = r F⊥ (sign by rotation sense)
1st: m_L g d_L = m_E g d_E  ·  2nd: F_eff d_eff = W d_load  ·  3rd: same form, d_load > d_eff