J.C.MacSwell

This cylinder problem? (below is your post currently numbered 30)

No. If they are moving with respect to one another, but not directly toward (collision course for respective centers of mass) or directly away, then they have angular momentum about their combined center of mass. The total angular momentum about their combined center of mass will not change in the event they did collide (of course it would be an off center collision in this case) nor would there be any change in their combined linear momentum.

If you have two objects that, in isolation, have no angular momentum, they may still in combination have angular momentum. Merged post follows: Consecutive posts merged If you have two objects that, in isolation, have no angular momentum, they may still in combination have angular momentum.

With a really powerful telescope you can see the cratery knoll from which JFK was shot from. How do you explain that if men never landed on the moon? Aliens?

bullet? Every action has an equal but opposite reaction. You cannot create angular momentum without creating an equal but opposite angular momentum.

It would look significantly different the way you describe, if the expansion was all happening in the same region or point, regardless of where, and regardless of whether you considered that point or region the "center".

He's going extinct.

Look at everything involved. The sum total of translational momentum will remain unchanged. The sum total of rotational momentum will remain unchanged. If you see rotational momentum where there was none before, then look carefully at the whole system, everything that was involved, and you will find something that will account for it, so that you are looking at the whole system, and you will see that angular momentum is conserved. A "single linear momentum" input, added other than in a direction intersecting the centre of mass of a system, always adds or subtracts angular momentum to/from the system, so you have to look at the bigger picture to see where it came from.

Momentum, both angular and linear, have precise definitions in classical physics. You are going to continue making the same mistakes until you understand them.

Not sure how well a fine red paste would hold up at infinite "g's" either.

This is correct. This is wrong. Force over time will affect translational momentum regardless of whether it is affecting angular momentum as well. They do not share a balance. They each must balance independently. If you input the same linear momentum, a force for a given time, the translational velocities will be the same. If you input the same energy, force over distance, they will be different.

I think it is certainly the accountant.

Good questions. Just keep in mind that these are not isolated systems and external force or forces are involved, as inputs to the original conditions. and angular and linear momentum are vectors and different concepts (You cannot add them together or transfer them, like you can with rotational and translational energies, which are scalars) 1. Where does the rotational energy come from? An external force. Same place the translational energy comes from. Can you not see that there are different inputs in each case? They are not isolated systems. In each case an external force is involved. If you assume the same force, it must act through more distance to transfer the same linear momentum in the second case, where the force does not act through the center of mass. This requires more energy. 2. What about angular momentum? How it starts rotation if all momentum transfers to translation part? Any answers? Again keep in mind these are separate concepts, angular and linear momentum are different. You cannot transfer only linear momentum in the second case, with a force not acting through the center of mass. As stated above, the same force (same vector quantity in the same direction) will act through more distance in order to transfer the same linear momentum. This takes more energy which accounts for the additional rotational kinetic energy. There is now angular moment in the system (second case) where there was none originally. Where did it come from? Now I will ask you, if you understand all of the above, how is angular momentum conserved? Look at the reaction to the force, the equal but opposite reaction. It had to have something to react against, something to accelerate in the opposite direction. Perhaps the simplest to understand would be a reaction against an identical, but mirror image system. Can you see how linear and angular momentum are each conserved in this case? The net sum of each for the combined system (which would be considered an isolated system with no external forces)would be zero, though twice the energy would be required. Merged post follows: Consecutive posts merged If you hit it with the same energy, the same force for the same distance, the classical mechanics solution does not say it will fly away with same high translation velocity. It does however say that if you impart the same linear momentum, the same force for the same amount of time, it will in fact fly away with same high translation velocity.

Obviously P=0 if it's an isolated system with no external forces, so nothing happens in either case.

Exactly. The angular momentum of one block can be transferred to the other and vice versa but the sum total does not change. The linear momentum of one block can be transferred to the other and vice versa but the sum total does not change. But the angular momentum cannot be transferred to linear. It is the rotational kinetic energy that is transferred to linear kinetic energy.

There is no transfer of angular to linear momentums. Both are constant for the system. (or would be with accurate simulator representation) You are showing (attempting but with the limitations of the simulator) a transfer of transfer of rotational kinetic energy and linear kinetic energy.

That doesn't hold though, in non-relativistic mechanics, where everyone agrees on simultaneity and time proceeds for everyone at the same rate. In SR faster than light in one frame would mean backwards in time in another. For example, given 3 points in space (with enough distance separation and moving relative to each other) sending messages faster than light, you could get tomorrows lotto winning numbers that you yourself sent off after reading them in the newspaper, with plenty of time to buy a winning ticket. (obviously can't happen and neither can faster than light communication)

Funny! I was thinking otherwise. At least I thought Fanghur was thinking otherwise.

... and was that equation believed to hold up, back in 1904, or was it believed to break down? Merged post follows: Consecutive posts merged Relative to an absolute frame, yes, and I believe it was generally thought that there was one

That was referring to the real world or SR where you obviously cannot accelerate anything to C, or to 2C which I picked arbitrarily. The point was that in Fanghur's classical space, you lose the ability to push back against anything as you approach C as well, from the perspective of an absolute and preferred reference. The math is different, but it is conceptually similar. Keep in mind we are not discussing the actual physics, just a "what if" based on the pre-Einstein expectations or Newtonian physics approaching the light speed limit. I don't see anything wrong with his conclusion based on the right set of assumptions. The question is more to the history- did scientists expect mass could be accelerated beyond C, and if so how, or by what means?

Isn't his point that you cannot "throw it back" from anything approaching light speed without invoking some "extra classical" force mediator? Similarly you can't claim to be able to break light speed in the real world by "throwing back" an equal weight at, say, 2C.

Infinites usually mean "answer no longer makes sense". Mass increase with velocity can be somewhat misleading, but in no case can it be with respect to the rest frame the mass is in at any given moment.

You would need something faster than the speed of light to mediate the force. So if your hypothetical "classical universe" did not have that, then nothing could get to that speed, but merely approach it. So I think your logic is reasonable given the right assumptions. It is somewhat analogous to SR where an infinite amount of energy would be required.

...then leave Mae West alone!

Thinking in SR terms we can manipulate time and one direction we choose to move in.