Do two objects attract each other even if they are not moving and are static?
Imagine placing two planets close together.
Both planets have no speed.
Do the planets still attract each other and collide?
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(2 votes)
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Hello 🤗 How would I calculate the current across the diode? Thanks in advance 🙏
Hello, I was just driving my 45cc car on a country road behind a tractor that was going 40. It was on a slight curve, so I couldn't see any oncoming traffic. Suddenly, a BMW 5 Series came speeding up from behind at 120 km/h and overtook me and the tractor without seeing oncoming traffic….
yes
to your actual confusion:
Yes, these are two different models. the ART is the “correct”, the Newtonian mechanic is an approach to it (the 99% of all applications that will ever come to you – here too – völlog is sufficient).
that different models represent a different description is not a problem. where the Newtonian theory can be applied, they still provide the same prediction (up to immeasurable tiny deviations)
The Gravity Act is simple: the force is proportional to the product of the masses by the distance square.
Yes, any crowds are pulling. Always. Regardless of the movement.
However, the resulting equations of movement depend on a variety of factors. With two bodies this is https://de.wikipedia.org/wiki/birth problem
This is quite classic newton mechanics. You don’t need a theory of relativity. Yes, you can also describe the force as a curvature of space time, but that makes it more complicated to understand and does not help with classical mechanics.
In your example: Yes, they’re coming together. Only the force between them and without initial movement there are no orbits or the like.
Yeah, I understand how you mean that. It helps me a little further.
My problem and my real question is:
Einstein says gravity is not a force but only the curvature
and Newton says gravity is a force.
Both models have their authorization and are applicable independently of each other (in different standards above all).
Even if both models are applicable and work it cannot be the gravitation a force and at the same time not.
So there is the force and (helps vllt?) at the curvature of space time, or is there both at the same time?
Both at the same time make no sense for me and I don’t understand.
I finally don’t want to calculate things, but I would like to know if gravity is really a force like Newton says or not a force and a curvature as Einstein says.
Thank you for your answer and look forward to more.
MfG
Gravity is obviously a force. Put yourself on the scale that shows you your weight (feelly as kg, actually it only measures the force and not the mass).
This, however, is not a contradiction to the statement of the ART that this force comes back to a curvature of the space time.
I believe you have two misunderstandings:
The first is “simple”: You don’t understand what the ART is. But you can teach yourself that, best by studying physics.
The second: We physicists do not know why something is. We just write how it is.
if you think of Newton, yes, we usually do that.
otherwise not.
otherwise you can only feel the power that the earth is exerting on you.
as it is “visible” that the son and the entire firmament turns around the earth every 24 hours.
with “obvious” I meant the phenomenological and it is perceived as a force
in the ART in the did not.
(but does not matter for the questioner)
The space-time curvature is a model presentation for explanation, calculation of gravity. “Seeing” in the direct sense cannot be, “only” the effect, namely the force, is noticeable, predictable.
Two planets close to each other can never rest, unless a counterforce (rotation around each other or a “stange” that keeps them at a distance) causes this state of rest.
Time curvature and the resulting force are not two things, but one and the same, inseparable.
First of all, Gravity completely independent of speeds. The question is already fully answered. This, however, still contains a rough mistake:
“Both planets have no speed.”
First of all, this cannot be because planets circle around their central body by definition, otherwise it would not be planets. A body in the planetary system without a circular path velocity around its central structure would fall straight into this central structure.
Secondly, each speed is relative to the arbitrarily selected reference system: When we say in practical everyday life: “The car moves forward with x km/h”, then we relate this speed indication to the underlying floor as supposedly “resting” body. But this soil circles around the earth’s axis, with the earth around the sun, with the sun around the Milky Way axis…
If you present two planets “without speed” in astronomical fields, you must first specify which system the two bodies should have the speed zero. This means nothing other than that both bodies have the same speed. This can be said objectively without giving a reference.
Where two bodies move at the same speed, they immediately collapse due to the mass attraction as soon as they are not stopped by a counterforce. This counterforce is the centrifugal force of planets.
This applies theoretically in everyday life also to tennis balls and dust grains. Here, however, due to the low masses and given distances, the attraction forces are so weak that we need a few decades or possibly centuries to effectively observe the body approach. However, there are special devices in physics labs with well-stored heavy lead balls whose approach can be successfully measured over a few weeks or months.
Since the gravity is independent of the speed (only depends on the mass of the objects), the two objects would attract.
And without further forces (external to stabilise your structure), this attraction would act more quickly. There is then a grimness towards each other and finally a collision.
But isn’t the time curvature responsible for the movement?
Without the curvature of time, the two objects wouldn’t wear themselves, would they? Because no movement can take place without time? Where’s my fault?
This is a partially understood interpretation of the general theory of relativity.
In your example, the classic laws of Newton are sufficient.
This can be found experimentally with simple means: take a cup, hang it on a thread, wait until it comes to a standstill.
Then cut the thread.
Does she fall, or does she remain hovering?
Perhaps it should be done better with an object that does not break so easily.
Not the movement produces the gravitation.
But isn’t the time curvature responsible for the movement?
Without the curvature of time, the two objects wouldn’t wear themselves, would they? Because no movement can take place without time? Where’s my fault?
I don’t understand your objection. Yeah, masses crumble the space. And yes, without time or space or space, there would be no movement. However, there would simply be nothing without space, even no matter.
Even if 2 people are resting next to each other, they exert a force of gravity on each other.
https://de.wikipedia.org/wiki/Newtonsches_Gravitationsgesetz
Yes, it’s both right: The Newtonian gravitational theory is the limit of ART for small speeds and small masses and large distances. And this is enough for (almost) all calculations of planet paths etc. In the solar system. I would only do the stress with the partial differential equations of the ART if necessary.
Yes, that makes sense, but the general theory of relativity says very carefully that the gravitation is not a force than this, but rather is the curvature of space.
And yes the newtonian bill is useful and works in the small and the ART(General relativity theory) works better in the big.
It can’t be both right, can it? If one says there is a force and the other says there is no force but only a curvature, then one is wrong, is it?
It’s not a shame.
This is the real question I’m looking for an answer.
I’m very grateful for all your answers.
MfG