8
   

Can an object be accelerating and yet -not- moving?

 
 
Ceili
 
  1  
Reply Wed 20 Feb, 2013 10:30 pm
The singular act of movement is acceleration.
If something is not moving, there is NO acceleration. If something is moving, it's either moving at a constant speed, decelerating or accelerating.


As for the original question.. at this very moment, I'm sitting pretty still and I believe that the earth is spinning, in an expanding galaxy in an expanding universe. So yeah, I guess.

roger
 
  1  
Reply Wed 20 Feb, 2013 11:12 pm
@Ceili,
That was my intuitive answer. It seems I was wrong.
0 Replies
 
maxdancona
 
  1  
Reply Thu 21 Feb, 2013 07:40 am
@Ceili,
Ceili,

Sorry but that is wrong.

Did you read the responses from the knowledgable people who have tried patiently (and not so patiently) to explain this?

Things that are "not moving" (have a velocity of 0) can have an acceleration at the same time (for an instant). This happens all the time in nature, it isn't that rare. Throwing a ball straight up is just one example given.

It is frustrating that after five pages of discussion, this simple math question with a simple answer still isn't resolved.

The correct mathematical answer is Yes. An object can be accelerating and not yet not moving.

Can we move on now?
0 Replies
 
dalehileman
 
  1  
Reply Thu 21 Feb, 2013 12:00 pm
@maxdancona,
Quote:
….. understanding math and science, intuition is worse than useless.
It's generally acknowledged, as I might have remarked above, that Intuition helped Einstein formulate his Relativity. I myself am an erstwhile inventor, depended heavily on Intuition. Always remember the general principle Max, nothing is entirely anything…...

Quote:
Your intuition is wrong.
Could well be

Quote:
Just ignore it.
Can't

Quote:
It is frustrating…...this simple math question…….still isn't resolved………. answer is Yes. An object can be …..accelerating and not yet not moving.
Yea Max but you're again emphazing the mathematical aspect of the situation, but God doesn't care about math, a purely humanoid invention

Of course so is Intuition. Still it insists, at the top of its trajectory for an instant of zero duration (whatever that means) the ball is experiencing no acceleration

Quote:
Can we move on now?
You may be excused, Max, with however many thanks for your participation
0 Replies
 
dalehileman
 
  1  
Reply Thu 21 Feb, 2013 12:05 pm
@Ceili,
Quote:
If something is not moving, there is NO acceleration.
The very crux of the matter, Ceili. In the nanomicrosecond when your limb comes into contact with the object but before it starts moving, is it really accelerating

Mathematically, apparently it is, and Math always predominates in the Scientist's thinking
engineer
 
  1  
Reply Thu 21 Feb, 2013 12:41 pm
@dalehileman,
dalehileman wrote:

Quote:
If something is not moving, there is NO acceleration.
The very crux of the matter, Ceili. In the nanomicrosecond when your limb comes into contact with the object but before it starts moving, is it really accelerating

True. If fact, it must be possible to have acceleration while at rest. If an object at rest does not experience acceleration, it can never move, ever. No acceleration means no change in velocity which means no movement.
dalehileman
 
  1  
Reply Thu 21 Feb, 2013 12:53 pm
@engineer,
Eng, I hear you, I understand the math aspect, and we apologize if it bothers some, but Intuition (Ceili's and mine) vigorously object to what appears to be a contradiction

Intuition insisting that a body feeling no acceleration can be accelerating

Of course we could be wrong
0 Replies
 
Falco
 
  1  
Reply Thu 21 Feb, 2013 05:42 pm
@dalehileman,
I didn't see your post there. Is my clarification of a semantic problem that math heavy?
I think it's pretty straight forward and explained decently in layman's term.
I think you'll get this concept easier if you start with the understanding of basic kinematic equations and conceptualizing the ideas behind the definitions and derivations.
I say that because intuition is just pattern recognition. This comes with doing many problems that force you to think and keep your brain completely engaged with the material. Good luck.
roger
 
  1  
Reply Thu 21 Feb, 2013 05:51 pm
@engineer,
That helps. It's still a little counter intuitive, but that helps.
0 Replies
 
dalehileman
 
  1  
Reply Thu 21 Feb, 2013 05:57 pm
@Falco,
Quote:
I didn't see your post there.
Forgive me Falco but my post where

Quote:
Is my clarification of a semantic problem that math heavy?
Sorry again Falco but can you send me a link to it

Quote:
I think it's pretty straight forward and explained decently in layman's term.
Probably so

Quote:
I think you'll get this concept easier if you start with the understanding of basic kinematic equations and conceptualizing the ideas behind the definitions and derivations.
Maybe hopelessly beyond me. In the first place math proves nothing, it's just circulation of electrical charges in a humanoid brain and second your Average Clod (me) isn't likely to understand unless the prop can be couched by ordinary everyday words in short sentences


Quote:
I say that because intuition is just pattern recognition.
Could well be

Quote:
This comes with doing many problems that force you to think…..
Forgive me once again Falco but what comes

Quote:
Good luck.
Thank you
Falco
 
  1  
Reply Thu 21 Feb, 2013 06:02 pm
@dalehileman,
dalehileman wrote:
Sorry again Falco but can you send me a link to it


http://able2know.org/topic/208160-3#post-5254748

dalehileman wrote:
Forgive me once again Falco but what comes

Intuition in physics.
dalehileman
 
  1  
Reply Thu 21 Feb, 2013 06:07 pm
@Falco,
Okay thanks Falco, evidently that's page 3 posting no. 748. But you might as well be explaining relativity to a squirrel
0 Replies
 
maxdancona
 
  1  
Reply Thu 21 Feb, 2013 07:47 pm
A question for the intuitive people here.

Can the slope of a line be upward and at a point where the value (i.e. on the 'y' axis) is zero?

Intuitively speaking that is.

dalehileman
 
  1  
Reply Fri 22 Feb, 2013 11:45 am
@maxdancona,
Max I could better address your q if you were to explain what "the value (i.e. on the 'y' axis) is zero" means

Also, if horizontal then is "upward" to the left or the right
maxdancona
 
  1  
Reply Fri 22 Feb, 2013 11:55 am
@dalehileman,
Consider this graph

https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcSra8O6-h5CBpAKpPBQLFQ9mdJVOryDCJCyTFnOXeol18eeJivMbQ

Y = 0 means that the point is on the horizontal line labeled "x".

"Upward" doesn't mean "horizontal". Upward means the height is increasing as you go from left to right. Horizontal means the height stays the same as you go from left to right.

So, does your intuition say the slope of the line can be non-zero when the y value is 0?
dalehileman
 
  1  
Reply Fri 22 Feb, 2013 12:06 pm
@maxdancona,
Quote:
Y = 0 means that the point is on the horizontal line labeled "x".
Yes, that much is pretty clear

Quote:
"Upward" doesn't mean "horizontal".
Surely I didn't give you the impression that I thought it was

Quote:
Upward means the height is increasing as you go from left to right.
See previous comment

Quote:
Horizontal means the height stays the same as you go from left to right.
See previous two comments

Quote:
So, does your intuition say the slope of the line can be non-zero when the y value is 0?
Of course not, but how does this bear upon whether I'm accelerating when I feel no acceleration
maxdancona
 
  1  
Reply Fri 22 Feb, 2013 12:11 pm
@dalehileman,
Well, let's make this a velocity time graph (the y-axis is velocity the x-axis is time). Y = 0 would mean that the velocity is zero (i.e. the object being represented isn't moving).

In this case the slope would be the acceleration. The velocity is increasing as you move from left to right meaning there is a non-zero acceleration even at y = 0.

So your intuition allows the it to happen in some cases and not in others? How strange.
dalehileman
 
  1  
Reply Fri 22 Feb, 2013 12:19 pm
@maxdancona,
Quote:
So your intuition allows the it to happen in some cases and not in others? How strange.
Max your point is well taken but I think the difficulty is semantic. I think of acceleration as a feeling when you're stopped while you define it in a purely mathematical concept

It's a lot like the apparent impasse between freewill and determinism
engineer
 
  1  
Reply Fri 22 Feb, 2013 02:22 pm
@dalehileman,
You assume you can always feel acceleration. If you are in a car going from 0-60 in 3(!) seconds, you would probably feel that right? It would slam you back in your seat. That is the force of gravity on you all the time. Jump off of a chair and while you are in the air, what does your intuition tell you about acceleration? Does it tell you that you are feeling enough acceleration to take you from 0-60mph in less than three seconds?
dalehileman
 
  1  
Reply Fri 22 Feb, 2013 02:37 pm
@engineer,
Quote:
You assume you can always feel acceleration.
. No but I suppose I might carry an instrument which when it reads zero tells me I'm stopped

Quote:
Jump off of a chair…..what does your intuition tell you….. that you are feeling enough acceleration to take you from 0-60mph in less than three seconds?
I have no idea, Max. But when I reach the peak of my trajectory my instrument supposedly reads zero
 

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