# Torque and joules

1. Apr 22, 2014

### Entanglement

Wikipedia says that the unit of magnetic dipole moments is calculated by Joule/B that means that the torque is measured by joules
I really doubt that, it seems non sense.

2. Apr 22, 2014

### Staff: Mentor

Torque has units of Force*distance. Usually expressed as N-m, but equivalent to Joules though I do not recommend that usage. (Usually Joule is reserved for energy, not torque!)

3. Apr 22, 2014

### Entanglement

How is that ???

4. Apr 22, 2014

### Entanglement

Energy equals the product of the force and the displacement along which the force is done

And the torque is the product of the force and displacement between the two forces, the concept of displacement isn't the same in both cases

Last edited: Apr 22, 2014
5. Apr 22, 2014

### Staff: Mentor

1 N-m = 1 J

6. Apr 22, 2014

### Staff: Mentor

We are talking about units, not about the definitions of torque and energy. (That's why energy is Joules while torque is in N-m, despite the fact the units are equivalent.)

7. Apr 22, 2014

### Entanglement

The units are are the same but their definitions are different

8. Apr 22, 2014

### Staff: Mentor

9. Apr 22, 2014

### Staff: Mentor

Right. (For example, one is a vector while the other is a scalar.)

10. Apr 22, 2014

### Entanglement

But I think that it's totally wrong to say that torque is measured by joules not just "unrecommended"

11. Apr 22, 2014

### Entanglement

Thanks jersey

12. Apr 22, 2014

jersey?

13. Apr 22, 2014

### Staff: Mentor

I'm not seeing that (I'm seeing n-m), can you link and quote it please.

14. Apr 22, 2014

### UltrafastPED

15. Apr 22, 2014

### Entanglement

16. Apr 22, 2014

### Entanglement

17. Apr 22, 2014

### Entanglement

18. Apr 22, 2014

### Entanglement

However, how is work done by a torque calculated ??

I know that work is calculated by f.d
I'm unable to apply that on non linear motion

19. Apr 22, 2014

### Staff: Mentor

What is the equivalent of "distance" if something rotates instead of moving along a line?

20. Apr 22, 2014

### BiGyElLoWhAt

$KE_{angular} = \frac{1}{2}I\omega ^2$