THIS IS NOT A SPIRAL.

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strawman

strawman



No, it's not.

Yes, I'm serious, look again!

Ok, put your finger on the screen and follow the supposed 'spiral' to the center!

Convinced?

Good.
 
Dave

Dave

Staff member
Okay. I hear ya. But answer me this:

If you have a circular object (such as an old vinyl record) and choose two spots along the same line - one towards the middle and one by the edge - and you start the object spinning, why and how do the spots go different distances at the same speed? The inner spot has a much smaller distance to cover than the one at the outer edge and even though they are moving at the SAME SPEED they reach the same spot at the same time. I know the RPMs are the same but they are still traveling different distances at the same speed yet are both starting and stopping parallel to each other.

That's always blown my mind a little.
 
C

crono1224

Dave said:
Okay. I hear ya. But answer me this:

If you have a circular object (such as an old vinyl record) and choose two spots along the same line - one towards the middle and one by the edge - and you start the object spinning, why and how do the spots go different distances at the same speed? The inner spot has a much smaller distance to cover than the one at the outer edge and even though they are moving at the SAME SPEED they reach the same spot at the same time. I know the RPMs are the same but they are still traveling different distances at the same speed yet are both starting and stopping parallel to each other.

That's always blown my mind a little.
Click to expand...
Its the difference between rotational speed and tangential speed. Every point on the record has the same rotational speed, but different tangential speeds depending on distance from the center.

Why runners are placed at different starting locations on a track, or why they are forced to cross over.
 
C

Chazwozel

Dave said:
Okay. I hear ya. But answer me this:

If you have a circular object (such as an old vinyl record) and choose two spots along the same line - one towards the middle and one by the edge - and you start the object spinning, why and how do the spots go different distances at the same speed? The inner spot has a much smaller distance to cover than the one at the outer edge and even though they are moving at the SAME SPEED they reach the same spot at the same time. I know the RPMs are the same but they are still traveling different distances at the same speed yet are both starting and stopping parallel to each other.

That's always blown my mind a little.
Click to expand...
They don't travel at the same speed.
 
Calleja

Calleja

Same rotational speed, different tangential speed. Remember physics class with radians and what not? That's the bit.
 
Zappit

Zappit

Staff member
If that was any brighter, I would have gone from colorblind to completely blind. Thank you. Now I still see it even when I close my eyes.

And yes, it is not a spiral.
 
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