Lever Arm Times Force Makes Torque - Rotational Dynamics and Orbital Mechanics Step by Step

Torque is the rotational analog of force, tau = r * F, the lever arm times the force applied perpendicular to it, measuring how effectively a force twists a body about a chosen axis. The arithmetic is exact only for stated lever arm and force in the ideal rigid-body model. Real systems add distributed mass, axis choice, friction, flexing, calibration, and measurement uncertainty.

A perpendicular lever arm and force form a checked torque. Exact arithmetic here means exact results for the stated model inputs; measured inputs still carry uncertainty and significant-figure limits.

highlighted = computed this step

A lever arm turns a force into torque

A lever arm of 3 meters with a 4 newton force makes 12 newton meters of torque.

\tau=3\times4=12\ \mathrm{N\,m}

Torque is kept distinct from energy

The role label says 12 newton meters, so the lesson does not relabel torque as joules.

\tau=12\ \mathrm{N\,m}