Lever Mechanical Advantage
Lever Mechanical Advantage
A lever multiplies force in proportion to the ratio of its arms — the oldest force-multiplying machine.
The mechanical advantage is MA = d_e/d_l and the load F_l = F_e·MA. where d_e and d_l are the effort and load arm lengths and F_e the effort force.
Inputs
F_e := 150 N=150 N
d_e := 1.2 m=1.2 m
d_l := 0.3 m=300 mm
The mechanical advantage is the arm-length ratio.
MA := d_e/d_l=4
The load lifted is the effort times the mechanical advantage.
F_l := F_e·MA=600 N
Results
A longer effort arm lifts a heavier load but through a shorter distance — force is multiplied, total work is not. This sets the leverage of bars, wrenches and wheelbarrows.
Assumptions & limitations
- Rigid lever, frictionless pivot.
- Forces perpendicular to the arms.
- Massless lever.