# I Calculation of torque, momentum

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1. Nov 30, 2017

### johnaguiar

Hi,
good afternoon

the problem is this: This device was assembled with the purpose of calculating the torque of a small motor. It measures the force F through a charge cell. The calculations performed for the moment were made using the data provided by the load cell and distance "d". However, the torque of an engine is traditionally calculated as the force established between the motor shaft and a load cell, as would be the case with the distance "d1". I would just like to know if the two moments are the same.

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2. Nov 30, 2017

### A.T.

Did you look at the definition of a moment? When the force is the same, but the lever arms are different, can the moments be equal?

3. Nov 30, 2017

### johnaguiar

Yes i know the definition. The problem is that also the force on the load cell would be different on the two cases.

4. Nov 30, 2017

### A.T.

What two cases? You posted only one crude diagram, and didn't even mark the motor.

5. Nov 30, 2017

### jack action

If I understood your drawing correctly, the torque is the same no matter where you measure it.

If you take a motor casing and its shaft, the torque is the same from the point of view of the casing or the shaft (one reacting to the other). If the casing is attached to a plate supporting it (like it seems to be in your drawing), you are just extending the casing. The reaction force will be smaller because of the larger 'casing', but that is just because the torque is the same.

6. Dec 2, 2017

### CWatters

That's correct.

Is there a brake on the flywheel or are you just interested in the torque while the flywheel is accelerating?