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.
τ=3×4=12Nm
Torque is kept distinct from energy
The role label says 12 newton meters, so the lesson does not relabel torque as joules.