Physics question...

[Lincsbodger]

OK, here what i think. The problem arises because time itself has so far not proven to be granular.

If time is granular, there must be a smallest unit of time whereby the world clicks along. The ball must at least be stationary for 1 quantum of time, however long that may be - if it does exist, its no longer than 10-43 seconds (being the shortest possible time that the weak nuclear force can act in)

On the other hand, if time isnt quantum but linear analog, then there is no point in time where the ball measurably stops,since no matter how short a time span you examine, here will always be a shorter timespan it can reverse direction in.

However, even if time is quantum, another consideration is that at the point it reversed direction, there has to be a quantum event that is at least equivalent to the collapse of the Qauntum Superposition of the ball. This then gets very tricky to determine, since the very act of trying to determine the speed of the collapse itself affects the speed collapse. The bottom line is that even on a quantum scale the duration of stationary non-movement is indeterminate because of Heisenberg Uncertainty Principle.

 

[JMLanders]

Lincs, sometimes it's best to remain quiet and let people think you're a fool than to open your mouth and remove all doubt

 

[Lincsbodger]

Lincs, sometimes it's best to remain quiet and let people think you're a fool than to open your mouth and remove all doubt

And you can provide arguments im wrong? Or was you just ****ing in the dark ?

Kindly provide counter arguments as to where im incorrect.

Conversely you could just admit you cant contribute to the discussion and stfu........

 

[imamartian]

OK, here what i think. The problem arises because time itself has so far not proven to be granular.

If time is granular, there must be a smallest unit of time whereby the world clicks along. The ball must at least be stationary for 1 quantum of time, however long that may be - if it does exist, its no longer than 10-43 seconds (being the shortest possible time that the weak nuclear force can act in)

On the other hand, if time isnt quantum but linear analog, then there is no point in time where the ball measurably stops,since no matter how short a time span you examine, here will always be a shorter timespan it can reverse direction in.

However, even if time is quantum, another consideration is that at the point it reversed direction, there has to be a quantum event that is at least equivalent to the collapse of the Qauntum Superposition of the ball. This then gets very tricky to determine, since the very act of trying to determine the speed of the collapse itself affects the speed collapse. The bottom line is that even on a quantum scale the duration of stationary non-movement is indeterminate because of Heisenberg Uncertainty Principle.

err.... yeah, that's kinds what i thought

 

[snico]

if i throw a ball directly up into the air... it will obviously slow down due to gravity, and return to Earth. So i assume at some point at the top of it's journey (parabola?), the ball is actually stationary.
But can we measure, accurately, the length of time it is stationary in the air?

It is never stationary in the air, not even for a second.

As soon as you throw the ball up, gravity is immediatley pulling the ball down. The object starts with an upward velocity from throwing. When you release the ball that upward force is gone, the only force acting on it is then gravity.

As soon as gravity overcomes the initial force, the ball will start to drop back to the ground. There is no hanging time of the ball, if there was it would be in a zero gravity situation.

The only thing you could determine is the time the ball started to drop back to earth, not the actual time it has stopped travelling upwards.......if that makes sense

 

[JMLanders]

And you can provide arguments im wrong? Or was you just p******g in the dark ?

Kindly provide counter arguments as to where im incorrect.

Conversely you could just admit you cant contribute to the discussion and stfu........

Deepest apologies- I had no idea that your opening gambit was a serious contribution. I also momentarily forgot your occasional lapse of sense of humour.

However, now that we have the usual pleasantries out of the way, as indicated in my opening usage of classical newtonian thinking, time tends to follow continuous rather than discrete properties.

I am intrigued by your wording here

there will always be a shorter timespan it can reverse direction in

- in particular the concept of time (sic) reversing direction

Further, if you could enlighten me of the precise meaning of

The bottom line is that even on a quantum scale the duration of stationary non-movement is indeterminate because of Heisenberg Uncertainty Principle.

in layman's terms, I for one would be most appreciative

 

[Lincsbodger]

And you can provide arguments im wrong? Or was you just p******g in the dark ?

Kindly provide counter arguments as to where im incorrect.

Conversely you could just admit you cant contribute to the discussion and stfu........

Deepest apologies- I had no idea that your opening gambit was a serious contribution. I also momentarily forgot your occasional lapse of sense of humour.

However, now that we have the usual pleasantries out of the way, as indicated in my opening usage of classical newtonian thinking, time tends to follow continuous rather than discrete properties.

This is entirely unproven and unknown. The nature of time at small scales is a topic of much debate, and the failure of Quantum Mechanics to provide a theory of time is one of its great failures.

I am intrigued by your wording here

there will always be a shorter timespan it can reverse direction in

- in particular the concept of time (sic) reversing direction

the ball reversing direction, not time.

Further, if you could enlighten me of the precise meaning of

The bottom line is that even on a quantum scale the duration of stationary non-movement is indeterminate because of Heisenberg Uncertainty Principle.

in layman's terms, I for one would be most appreciative

the smallest possible unit of time in which we can record an event is the Planck Time, 0.539 E-43 seconds. This is the shortest amount of time a particle interaction can take place. To be any shorter, the two particles woudl have to be closer, and then the woudl become indeterminate from one another. This still may not be the shortest interval of discrete time.

The Hiesberg Uncertainty Principle states that you the act of observing affects the observation at a quantum level. hence you can determine the velocity of an electron but not its position, or you can determine the postion of an electron but not ist velocity.

If there is a point where the ball is stationary, it must occur at a point where its direction reverses in less than the Planck length, in less than the Planck time. we cannot determine at that moment both the position of the ball and the velocity of the ball. Hence we wouldn't be able to determine if it stops or instantly reverses direction.

In any case, we as humans, even the sharpest of us, cant perceive any event shorter than about 100 milliseconds, and the ball most certainly doesnt stop for that long.

 

[LastMagicBean]

I realise I'm going to be completely f*cked for saying this .....But.....



Surely the answer lies in the 'definition' of 'stationary'.....
What i mean is.......
In basic terms, if a ball travels at 10mph in an upward direction and slows to 9,8,7,6,5,4,3,2,1.....Zero..........

Then presumably it's fall would START from zero..............
So at zero point, Zero, could conceivably be called Stationary by definition...?????

I'll shut up........

 

[Lincsbodger]

I realise I'm going to be completely f*cked for saying this .....But.....



Surely the answer lies in the 'definition' of 'stationary'.....
What i mean is.......
In basic terms, if a ball travels at 10mph in an upward direction and slows to 9,8,7,6,5,4,3,2,1.....Zero..........

Then presumably it's fall would START from zero..............
So at zero point, Zero, could conceivably be called Stationary by definition...?????

I'll shut up........

even if the ball move just one atoms width, its not stationary. It may not be stationary if it moves less than 1 atom, it might move 1 electron's width, but even then it might no be staionary. The smallest possible distance is the Planck length, so if it only moves 1 Planck length it might be stationary, except quantum physics prevents us from observing and measuring it.

Hence its never possible to determine a point where its truly stationary in space.

But it all hangs on what the shortest possible unit of time is, or isnt, as the case may be. You have no idea how complicated this question is to resolve.

 

[JMLanders]

the smallest possible unit of time in which we can record an event is the Planck Time, 0.539 E-43 seconds. This is the shortest amount of time a particle interaction can take place. To be any shorter, the two particles woudl have to be closer, and then the woudl become indeterminate from one another. This still may not be the shortest interval of discrete time.

Are you suggesting then that the ball remains stationary for one planck unit?

The Hiesberg Uncertainty Principle states that you the act of observing affects the observation at a quantum level. hence you can determine the velocity of an electron but not its position, or you can determine the postion of an electron but not ist velocity.

Sorry - no offence but I'm struggling with this due to the typos. I'll research and get back to you.

If there is a point where the ball is stationary, it must occur at a point where its direction reverses in less than the Planck length, in less than the Planck time. we cannot determine at that moment both the position of the ball and the velocity of the ball. Hence we wouldn't be able to determine if it stops or instantly reverses direction.

Does this not contradict the definition of a planck unit?

In any case, we as humans, even the sharpest of us, cant perceive any event shorter than about 100 milliseconds, and the ball most certainly doesnt stop for that long.

Perception isn't relevant, surely. It's what a physical (quantum) limit is that counts

 

[PrenticeBoyofDerry]

If you throw a ball up with a force less than that of gravity, it won't leave your hand.

It will, it will float away.

As for calculations, there are simple (school child) formulas that work it out.

Yes simple school boy maths
Vfinal²=Vinitial²+2ad where d is distance above the ground
set Vfinal=0 and solve for d
problem solved, next question please!

 

[JMLanders]

The other thing that we aren't mentioning overtly is relativity itself. If you attached a camera onto a ball following and filming the original ball, then according to the camera shot, neither ball is moving.

It is also entirely possible to attach a camera onto another moving object which is varying it's own velocity in such a way that the original ball always seems to be moving at a constant speed. Therefore, it never stops for any length of time in terms of this sphere of reference.

 

[PrenticeBoyofDerry]

qué

 

[JMLanders]

If you throw a ball up with a force less than that of gravity, it won't leave your hand.

It will, it will float away.

I beg to differ.- if a rocket's engine hasn't created enough force (propulsion) to overcome the force of gravity, then the rocket will not leave the ground. The analogy with the above holds

 

[snico]

Its very simple, the ball WILL become stationary as the effect of gravity takes over the initial upward force from the throwing the ball up.

BUT....the time it is stationary is so small, and unmeasurable, it cannot be determined. It does get very complicated to explain. I have tried to explain in it laymens terms