# Can Something Exist for Zero Seconds?

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Should it be "approaching zero seconds" to avoid the wrath of Heisenberg? Is it okay to have fuzzy position info when we're concerned with velocity?

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1 hour ago, swansont said:

Velocity is a vector, so you should have stopped after saying it has each velocity for precisely 0 seconds.

edit: and now I see Strange has made this same point.

you need an acceleration to get the speed: before v=0.

you can set t=0 at the time of the acceleration event but the time exists before v=0 and after v returns to 0

Edited by stephaneww
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2 hours ago, stephaneww said:

you need an acceleration to get the speed: before v=0.

you can set t=0 at the time of the acceleration event but the time exists before v=0 and after v returns to 0

I don’t understand why you think this matters. Does it change the fact that each velocity exist for only a single value of time?

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1 hour ago, swansont said:

I don’t understand why you think this matters.

I think I didn't understand the initial question then.

1 hour ago, swansont said:

Does it change the fact that each velocity exist for only a single value of time?

Yes, of course, that doesn't change anything.

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8 hours ago, koti said:

If you find a minute, could you rephrase that?

Throwing a ball up has it start with a velocity v coming out of your hand. There is no force causing it to accelerate upward, but there is a force causing it to accelerate downward: gravity.

So, from v, the velocity slows with the acceleration due to gravity until it stops. But, then, it starts going down, still accelerating due to gravity. This trajectory is symmetric about the point at the top where the velocity is zero. So, for any other point, there is a partner where the ball has the same speed. But for each speed, the ball has that velocity for 0 seconds.

There must be a time or two that the ball is at each speed, but it is at each speed for no time at all.

8 hours ago, Strange said:

The velocity is constantly changing and so the ball has any specific velocity for 0 seconds.

(I disagree with the last part. The ball may have the same speed twice (for zero seconds each time) but will never have the same velocity.)

Indeed, speed, not velocity. You've earned yet another cookie for catching my mistakes.

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• 4 weeks later...
On 8/25/2019 at 7:24 PM, Farid said:

Hi everyone,

I wanted to create this thread because of the duration of time itself. Time cannot have a duration of more than zero seconds. Time having a duration of more than zero seconds means that when time is one second, an amount of time that is the duration of that time passes and time is still one second, which is impossible.

Your question brought  this video and this equation to mind. I may be jumping the gun presenting it before reading the whole thread? The first time I saw the equation my mind went, (What? Zero?), but then the video made sense of it.

Maybe, you will see the same relation to your question that I did... of course, maybe I’m wrong?

Maybe your logic is like. I have one orange. Someone gives me another so, now I can no longer have one orange. The video still might help?

Edited by jajrussel

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