A friend of mine noticed that the units of torque, N x m, should be the same as the units of work, again, newtons times meters. Yet torque is expressed in newton-meters and work is expressed in joules.

 

What's the difference? I think it has something to do with the difference between a cross and dot product, but that's just conjecture on my part.

 

Thanks!

N

Torque is a vector, and work is a scalar. Also, specifying torque and work in the same units could lead to confusion.

As much as anything, it is just tradition. It probably started from the fact that they are different quantities, so the units were just given in different ways. Also, the torque, being a moment arm times a force, the units as commonly expressed reflect that.

 

But, that said, they are both still mass*length^2/time^2 as the base units.