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A 1 kg ball is attached by a 1 meter string to a 2 kg ball. The system is rotating at 1 rps in space far away from any other mass. At t1 the string breaks.Is there any change in angular momentum? Is there any change in linear momentum?
Also is the momentum carried Out in all directions by the sound waves included in your calculations?
Sound waves carry energy but not momentum. That means a perfectly elastic collision between objects cannot make any sound. The inelastic collision can, but if the system is moving through a medium which carries sound (air), they're probably losing momentum due to friction with the air. That would constitute an external force upon the system.This is not the case with Earth as a system. It makes no sound as it travels through space.
That is incorrect, for your and subsequent readers information it can be calculated usingMomentum = energy/phase velocity
As Halc pointed out, the momentum carried by them is zero.The symmetry argument has the advantage of being quick and obvious, which is why I used it.Halc clarified that, a wave carries energy away from the systemIn an elastic collision, no energy is lost so there can be no wave.A wave that does not exist can not carry momentumFor some reason you have brought it up again.
“So, for example, you can not convert linear momentum into angular momentum”
So you have made clear what you consider the boundaries in earlier posts so try this heat engine for an example of linear to rotational/angular momentum.
Ignoring second-order effects such as thermal winds, the source of kinetic energy is the rotational energy of the planet, so it must eventually stop spinning.
And still, at every stage where a molecule hits a molecule, momentum is conserved so the momentum overall is conserved.
the frictional coupling of the atmosphere and the surface of the earth which are not perfectly elastic coupling therefore sound waves do exist and are transferring momentum out symmetrically, which as stated previously under the laws of conservation, a percentage of said momentum came from the angular momentum of the solid earth/atmosphere total.So as I stated before, for you position to be credible you need to address this continuous transfer away from the angular momentum budget.
The coriolis force happens because momenta are conserved.
yes agreed but it starts out as linear momentum and ends up with rotation/angular momentum
which still leaves outstanding an explanation or comment as to this aspect;
which is a pretty standard daily fluctuation, which represents Δ of approximately 6.55 x 10^20 Joules of kinetic energy
You can't say if that's a change in momentum or moment of inertia.
...OK, I have a system with say linear momentum of 100 kg.m/sec in the x direction relative to inertial frame F.I add 1 KJoule of energy to the system. What is its momentum after I do that?You can have anybody you like 'looking' at the system.More specifically, how much kinetic energy does it have if I add 1 KJoule of heat to the system? That question actually can be answered....
But it is currently postulated most of daily variations are credited to exchanges of momentum between the solid earth and the atmosphere.
Heat can generate rotational kinetic energy, angular momentum in a closed system (no mass in/out, just heat energy in/out).
...Quote from: Jaaanosik on 11/10/2020 03:16:50Heat can generate rotational kinetic energy, angular momentum in a closed system (no mass in/out, just heat energy in/out).Kinetic energy yes. Momentum, no. An internal combustion engine gets its rotational kinetic energy basically by turning chemical energy into heat, and that heat into kinetic energy. But that doesn't change the momentum of the engine one bit. The angular momentum gained by a revving engine comes from external torque applied to it by the engine mounts.
Just for clarity for those that may not understand your point below is quite a good demonstration.
It is action and reaction.
Here is the problem that might be in the way of agreeing what we say.We start an electric motor on ISS, floating, stator and rotor spin opposite way.The total net angular momentum is going to be zero.
Does the motor have an angular momentum as a system?
Would the system behave differently upon application of an external force when motor is not spinning compared to when the motor is spinning?
Quote from: Halc on 11/10/2020 04:44:00Quote from: Jaaanosik on 11/10/2020 03:16:50Heat can generate rotational kinetic energy, angular momentum in a closed system (no mass in/out, just heat energy in/out).Kinetic energy yes. Momentum, no. An internal combustion engine gets its rotational kinetic energy basically by turning chemical energy into heat, and that heat into kinetic energy. But that doesn't change the momentum of the engine one bit. The angular momentum gained by a revving engine comes from external torque applied to it by the engine mounts.It is the other way around.There is no external torque. If engine is not running then where is the external torque? Doing what exactly?Nothing. No external torque. There is nothing external spinning the engine, is there?
Quote from: Jaaanosik on 11/10/2020 03:16:50Heat can generate rotational kinetic energy, angular momentum in a closed system (no mass in/out, just heat energy in/out).Kinetic energy yes. Momentum, no. An internal combustion engine gets its rotational kinetic energy basically by turning chemical energy into heat, and that heat into kinetic energy. But that doesn't change the momentum of the engine one bit. The angular momentum gained by a revving engine comes from external torque applied to it by the engine mounts.
The torque comes from the engine itself.
Why car engines have the torque as their specification?
It is action and reaction. The first action is engine running then the reaction is engine mounts 'counter-torque', preventing the engine block from spinning.
Here is the problem that might be in the way of agreeing what we say.We start an electric motor on ISS, floating, stator and rotor spin opposite way.The total net angular momentum is going to be zero.Does the motor have an angular momentum as a system?
I pretty much put all the posts from those advocating violations of conservation of angular momentum in this topic.
Should this stuff be in teh "that can't be true" forum?