Torqua

Meet Torqua, who knows leverage is everything: where you push matters as much as how hard.

Torque is the turning effect of a force. It is the cross product of the lever arm r, from the pivot to where the force acts, and the force F. Its size is rF sin θ, where θ is the angle between them. Only the part of the force perpendicular to the lever arm does any turning, and pushing straight along the arm does nothing.

Example: a 0.3 m wrench with a 100 newton push at right angles gives 30 newton-metres. Use a 0.6 m wrench and the same push gives 60 N·m. That is why a long handle loosens a stubborn bolt.

Torque is everywhere: doors have handles far from the hinges, bicycles use pedal cranks, and car engines are rated by the torque they deliver.

Torque is a vector, pointing along the axis of rotation by the right-hand rule. Its unit, the newton-metre, has the same dimensions as the joule, but torque is not energy.