Question about two torques on rigid body.

AI Thread Summary
A massless rigid rod with motors on each end accelerates attached discs, raising questions about net torque and force. When both discs spin in the same direction, they create a torque couple, causing the rod to rotate about their common axis. However, if the discs spin in opposite directions, torsion occurs, complicating the motion. The discussion emphasizes the importance of understanding torque interactions in rigid body dynamics. Overall, the behavior of the system depends significantly on the direction of the discs' rotation.
Crappinni
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Hi, here's the question:

A massless, rigid rod has motors attached on each end. The motors are each connected to a massive disc, and the motors accelerate the discs in the directions indicated by the arrows.

Due to the torque from the each motor on its disc and hence that on the rod and other disc, is there a net torque or force?

Assuming there are no other forces (like gravity or friction), what will happen?

Additionally, if both discs are spun in the same direction, what happens?

Thanks!
 

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What do you expect to happen?
Clearly, the rod will rotate along with the discs about their common axis.
 
R Power said:
What do you expect to happen?
Clearly, the rod will rotate along with the discs about their common axis.

Thanks for answering.

I'm sure that's the case when both discs are spun the same way because of the torque couple. But when they are spun in opposite directions, why would they have a common axis?
 
I'm sure that's the case when both discs are spun the same way because of the torque couple. But when they are spun in opposite directions, why would they have a common axis?
in case discs are spun in opposite directions there will be the case of torsion.
 
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