Last week I wrote about a couple. This week it’s a different kind of couple that I’m writing about…
The resultant moment of a couple is called a torque. This is not to be confused with the term torque as it is used in physics, where it is merely a synonym of moment. Instead, torque is a special case of moment. Torque has special properties that moment does not have, in particular the property of being independent of reference point, as described below.
This is my new favourite confusing paragraph from Wikipedia. If you followed that on your first reading, you’re doing well. I can only assume that when it says “Torque has special properties that moment does not”, it means “Torque has special properties that not all moments have”. But my assumption could be wrong, so I’d better not try to fix things—I might just make them worse.
Also, I generally think of mechanics as a subset of physics. This means that “Don’t confuse torque (mechanics) with torque (physics)!” is just confusing.