Is engine torque a static force?

[vysqn]

Maybe stupid question but it confuses me:)
For Example engine produces 100Nm of torque at 3000RPM. So that's mean that this 100Nm at 3000RPM in this particular moment is static force? Because torque doesn't move anything. If it start to spin, it doing work and work over time is POWER. (~43Hp at this example)
Is this correct?

Thank's !

 

[jrmichler]

If the engine is producing 100 Nm of torque to a shaft spinning 3000 RPM, then the shaft is delivering 42 hp of work to whatever is connected to the shaft.

But the engine, which is stationary, has an equal 100 Nm of reaction torque. The reaction torque is doing zero work because the engine is not moving.

If the shaft is not connected to a load, just spinning free, then the engine is producing zero torque and zero power. The engine may be capable of producing 100 Nm of torque, but it is only producing that torque if it is connected to an appropriate load.

 

[vysqn]

"The reaction torque is doing zero work because the engine is not moving."
So that's mean torque is static force. Back to the example, at 3000rpm it produces 100Nm on this particular snapshot in time

 

[jim hardy]

So that's mean torque is static force

You're trying to over-define.

Torque is torque.
Torque can be static as when you're pulling on a wrench and the bolt has not yet begun to turn because you have not yet overcome friction.
Torque can be dynamic (ie in motion) after the bolt has begun to turn and is now moving against friction.

 

[vysqn]

So, dynamic torque = work

 

[CWatters]

If it helps...The equations for linear an rotational motion are similar...

Work = force * displacement
Work = torque * angular displacement

Power = Work/time
So..
Power = force * velocity
Power = torque * angular velocitySo torques work like forces. If the torque (or force) isn't moving it's not doing any work. If it is moving then it is doing work.

 

[CWatters]

In your example the shaft is rotating so it's doing work. The reaction force trying to move the engine in its mounting blocks is not moving so it's not doing work.

 

[vysqn]

The reaction force trying to move the engine in its mounting blocks is not moving so it's not doing work.

Don't understand - can You put more information here

 

[CWatters]

"For every action there is an equal and opposite reaction".

When the engine turns the drive shaft clockwise there is an equal but opposite reaction torque that tries to turn the engine block anti-clockwise. However the engine block is fixed to the car so it cannot rotate. The engine does work on the driveshaft. The engine block does not do work on the chassis.

 

[jim hardy]

So, dynamic torque = work

no.

you're trying to ascribe meaning instead of looking it up.

Torque is torque. Work is torque X displacement by rotation, as stated more eloquently by @CWatters in post 6.

Work = torque * angular displacement

The mind will concatenate words because they sound good even if the concept conveyed is dead wrong. That's how you get "Word Salad" ..

slide 12 here https://slideplayer.com/slide/4773534/

 

[vysqn]

Thank You Guys!

I will analyze those informations for better understanding this principals.