A watt of power multiplied by a second of time has an agreed upon name called joule, but a watt second is also a perfectly valid SI name.
A watt is a joule of energy divided by a second of time, this is a rate, joule per second is also a valid name similar to nautical mile per hour and knot being the same unit.
Multiplication vs division, quantity vs rate, see the relationship? Units may have different names but are equivalent, both the proper name and compound name are acceptable.
A watt hour is 3600 joules, it’s more convenient to use and matches more closely with how electrical energy is typically consumed. Kilowatt hour is again more directly relatable than 3.6 megajoules.
Newton meter and Coulomb volt are other names for the joule. In pure base units it is a kilogram-meter squared per second squared.
So when I torque all 20 of my car's lug bolts to 120 n-M, I've exerted 2/3 of a W-h? So if it takes me 4 minutes, I'm averaging 10 watts? That's neat. I wonder what the peak wattage (right as the torque wrench clicks) would be; it must depend on angular velocity.
Newton meter as a unit of energy is not the same as the newton meter unit of force for torque.
The energy unit meter is distance moved, while the force unit meter is the length of the moment arm.
This is confusing even though valid, so the energy unit version is rarely used.
You can exert newton meters of force while using no energy, say by standing on a lug nut wrench allowing gravity to exert the force indefinitely unless the nut breaks loose.
Ah! I guess that explains the "f" for "force" in the imperial abbreviation "ft-lbf", to distinguish it from work. I wonder if there's ever been an analogous variant for metric such as "Nmf"...
Hmm, I thought lbf was to distinguish the force unit from the mass unit (1 lbf = G * 1lb mass)
It seems the common thread is that the f means to introduce G, but not exactly. In my own research, the AI summaries are about as sloppy as I've ever seen, due to the vague and often regional differences (with the difference between ft-lb and lb-ft sometimes being described as relevant, as well).