On torque and work having same units

AI Thread Summary
Torque and work share the same SI units of N·m and Joules, respectively, but they represent different physical concepts. Torque is a vector quantity, while work is a scalar quantity, which means they cannot be interchangeably expressed without causing confusion. Although both quantities can be measured in the same dimensional units, using Joules to describe torque may mislead others. The relationship between torque and work is highlighted by the fact that applying a certain torque over one radian of rotation requires an equivalent amount of energy in Joules. Clear distinctions in terminology are essential for effective communication in physics.
benabean
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In rotational motion ,

the units for torque, \tau = r \times F,

are N \cdot m


and for work done by a torque,

W = \int_{\theta1}^{\theta2} \tau \cdot d\theta, are Joules.

Yet both these quantities are homongenous/ have same SI units.

Is it so wrong to quote torques in Joules? If so, why?
(And vice versa)

b.
 
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Torque and work are two different types of quantities. Work done done is a scalar quantity, whereas torque is a (pseudo)vector.

As a matter of interest, you are not even supposed to say mN for torque, but Nm.

For more, read http://en.wikipedia.org/wiki/Torque" .
 
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N-m or N*m would be even better.
 
they have the same dimensions, but so do the frequency of a sound wave and the rate constant of a first order chemical reaction. Does that mean you can express a rate constant in Hz??
 
you can use the same units if you want, but it might confuse some folks if you used Joules to describe a measure of torque.

turning a shaft against X Nt-m of torque exactly one radian of twist requires X Joules of energy. measuring angles in radians is dimensionless (being the ratio of like-dimensioned quantities: arc length divided by radius).
 
Thanks guys, you're help is very appreciated.
 
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