davidcoton,

We were discussing rotation and acceleration, and which causes which. Your statement was that "The rotation does not cause acceleration. Acceleration causes rotation."

Well, let's see. According to our hero Newton we have a formula for that. The magnitude of the centripetal acceleration is related to the tangential speed and angular velocity as follows:

a = v^2 / r = ω^2 r

Written that way it looks like the rotation ω is causing the acceleration. Increase ω and a increases.

But we can quite validly rewrite that equation as:

ω = root(a / r)

Now it looks like the acceleration is causing the rotation. Increase a and ω increases.

Hmmm...this looks like a chicken and egg problem. Which causes which?

I'm not sure why you insist that one is the cause and the other is the effect.

I think "causes" is the wrong way to look at it. The rotation and the acceleration are in balance. As the equation describes. That is what equations are, a balance between one side and the other.

We could consider an even simpler example by way of analogy. Say two equal masses, m1 and m2, resting on the pans of some scales in balance. Your claim above is like saying that m1 does not fall down because m2 is holding it up. Another might say, m2 does not fall down because m1 is holding it up.

I say, it's a stable system. Both m1 and m2 stop each other from falling down. Take away either and the other falls down.

So it is with centripetal acceleration and rotation.