Torque is the turning effect of a force about a pivot, also called the moment of a force. It depends on how hard you push, how far from the pivot you push, and the angle you push at: τ = rF sin θ.
That is why a longer spanner loosens a tight nut more easily, and why you push a door near its edge, at right angles, rather than near the hinges.
| Force (F) | 200 N |
| Distance from pivot (r) | 0.4 m |
| Angle between force and lever (θ) | 90 degrees |
| Torque (N·m) | 80 |
| Torque at 90° (N·m) | 80 |
Pushing at right angles gives 80 N·m.
Try this example →| Force (F) | 200 N |
| Distance from pivot (r) | 0.4 m |
| Angle between force and lever (θ) | 30 degrees |
| Torque (N·m) | 40 |
| Torque at 90° (N·m) | 80 |
At 30° the same push gives only 40 N·m, half as much.
Try this example →τ = r × F × sin θ, where r is the distance from the pivot, F the force and θ the angle between them.
Newton-metre (N·m).
When the force acts at 90° to the lever arm, so sin θ = 1.
No. Both can be written in N·m, but torque is a turning effect, while work (in joules) is energy transferred.