« on: 15/05/2020 01:49:24 »
...]The angular velocity of the axle is constant, changing only when the weight is added or removed. That means the torque is momentary. No additional torque is needed to rotate something that's already rotating. Instead of asserting all these things, why don't you consider the implications of your assertions, which run into contradictions. If there is continuous torque on the axle, why does its angular velocity not change after that moment when the weight is added. That's would be a contradiction.Halc,QuoteYou can attach the weight to the rotating wheel axle on the ISS and it is not going to precessThere is no weight on the ISS.
The bold statement is true for a rigid body, a mass, ...
The bold statement is not true for the rotational inertia.
This is very similar to the following scenarios:
- holding a weight in a stretched hand, no potential energy change for the weight but it costs energy to hold the weight.
- an astronaut going in a circle around the ISS with the jets on his back costs energy though the kinetic energy does not change for the astronaut in the ISS frame.
- hanging the weight on a string, no potential energy change for the weight and it does not cost any energy.
- the astronaut going in a circle around the ISS attached with a string, no kinetic energy change and it does not cost any energy.
... the same results as the above but no energy cost.
The torque rotating the angular momentum is doing work even though it appears there is no potential energy change.