Torque wrenches use Newtons (correct) and Foot Pounds (Wrong)

[Chronos]

Nitpick: don’t you need to specify g? Torque and Energy should be force x distance not mass x distance iirc.

No, you don’t need g. Pounds are inherently a measure of force already; it’s when you’re using pounds as a unit of mass that you need to specify g.

And if you really want to nitpick, torque is considered by physicists to be a pseudovector, not a vector. Basically, whenever you need to use a right-hand rule to define the direction of a quantity (such as the cross-product of any two true vectors), it’s a pseudovector.

If I finally understand torque, it’s why levers work, right?

Correct. Or in more detail, the rotational form of Newton’s 2nd law is why levers work. If your lever isn’t accelerating, or has a relatively low moment of inertia compared to the things at its end (usually a good approximation), then it has approximately zero net torque on it. Which means that the torque you’re putting on one end of the lever is equal in magnitude to the torque your load is putting on the other end of the lever. Torque is force times distance from the fulcrum, so if you’re (say) further from the fulcrum, you need less force to get the same torque.

[Newton_meter]

It’s a little late, but I just checked both of my torque wrenches, and they say Newton meter.

[Shade]

Torque is actually a pseudovector, but so what? Velocity is a vector and the speed of light is a scalar, but they can still be compared. And they still use the same units.

DOH! Good point, never mind. Sorry, guys.

[sailor]

*Originally posted by Newton meter *
**It’s a little late, but I just checked both of my torque wrenches, and they say Newton meter. **

They call you by name?

[KP]

Torque is actually a pseudovector, but so what? Velocity is a vector and the speed of light is a scalar, but they can still be compared. And they still use the same units.

Um… no. As you noted, a velocity is a vector, and the speed of light -or any speed- is a scalar. You can’t directly compare them. Velocity is a vector that MUST have a speed and a heading.

In some cases you can trivially compare the speed component of a velocity vector with a scalar speed, but in other cases, that is not just useless but will earn you (and “earn” it you will) a world of hurt.
*
“Captain, we fired our lasers at the enemy ship at 300,000 km.”
“So it will be destroyed in roughly a second, then? Good.”
“Actually… no, sir.”
“No? Has someone changed the value of C? Explain yourself, Lieutenant!”
“Oh, our laser bursts still travel at roughly 3x10^5 km/sec. But they weren’t aimed at the enemy ship. Due to a sign change in heading by Gunnery mate Bassackward who won’t believe in the difference between a vector and a scalar, we fired on our flagship instead.”
“Our Flagship? Dear god! What do we do now?”
“Given the disparity in firepower between us and the flagship, and the fact that her main guns are powering up, I’d say… die, probably”
*