M = F·r

Torque from force and lever arm

Only the force component perpendicular to the axis produces torque.

MINTSI
01

Inputs

Moment about the axis.

Force perpendicular to the arm; resolve angled forces first.

Perpendicular distance from line of action to axis.

02

Result

Select a target and calculate.

Technical principle schematic
rFM
Calculation

M = F · r

Only the force component perpendicular to the axis produces torque.

Understand the inputs
  • Torque MMoment about the axis.
  • Tangential force FForce perpendicular to the arm; resolve angled forces first.
  • Effective lever arm rPerpendicular distance from line of action to axis.
Example

500 N on a 0.2 m lever produces 100 N·m.

Assumptions and limits

Force is tangential; friction and dynamics are excluded.

Sources