# The Naked Scientists Forum

### Author Topic: What happens to an object moving in a circle at light speed?  (Read 6219 times)

#### alancalverd

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #25 on: 16/09/2015 12:12:44 »
Your problem is the obstination to want to use  equations which are valid only for velocities different from c. If you used those which are always valid, for all velocities included c, you wouldn't need to "climb on the mirrors"

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lightarrow

I don't have a problem! I'm trying to answer the original question. By all means choose any equation you like that consists with experimental evidence, and tell us how much energy we need to expend to accelerate an object for which m0≠ 0 to the speed of light, then how much force is required to constrain it to a circular path with a constant tangential speed c.

#### lightarrow

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #26 on: 16/09/2015 16:08:38 »
Tangential Radial (centripetal) force. In modulus: F = (E/r)*β2

E = energy.
β = v/c

For a body with mass: E = mc2γ; γ = (1-β2)-1/2
For a body moving at c: β = 1.

About the energy needed to accelerate a body to light speed, see "E" up. For a photon you can write E = h*f if you like.

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lightarrow
« Last Edit: 17/09/2015 17:33:08 by lightarrow »

#### jeffreyH

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #27 on: 16/09/2015 20:51:37 »
If we take the value we end up with . How do you come to this determination? Beta may equal 1 according to your previous post but then you are taking the square root of zero and dividing it into 1. How is that valid? None of this has a bearing upon c.
« Last Edit: 16/09/2015 20:54:29 by jeffreyH »

#### PmbPhy

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #28 on: 16/09/2015 22:22:01 »
Tangential force. In modulus: F = (E/r)*β2

E = energy.
β = v/c

For a body with mass: E = mc2γ; γ = (1-β2)-1/2
For a body moving at c: β = 1.

About the energy needed to accelerate a body to light speed, see "E" up. For a photon you can write E = h*f if you like.

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lightarrow
Did you know that in his 1905 paper on special relativity Einstein got the expression for the transverse mass wrong? Ohanian explains the error in his book Einstein's Mistakes located at http://www.newenglandphysics.org/other/Ohanian_Einstein_error_1905.pdf
http://www.newenglandphysics.org/other/Ohanian_Einstein_error_1905.pdf

#### lightarrow

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #29 on: 17/09/2015 14:37:38 »
If we take the value we end up with . How do you come to this determination? Beta may equal 1 according to your previous post but then you are taking the square root of zero and dividing it into 1. How is that valid? None of this has a bearing upon c.
Sorry, I'm a bit "slow" in these days, what do you mean exactly? Are you referring to the equation F = m*a when F is in the same direction of velocity?

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#### alancalverd

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #30 on: 17/09/2015 16:40:47 »
Tangential force. In modulus: F = (E/r)*β2

E = energy.
β = v/c

For a body with mass: E = mc2γ; γ = (1-β2)-1/2
For a body moving at c: β = 1.

Agreed, so as v→c, E → ∞ if m ≠ 0

And the radial force required to maintain circular motion of a massive body at v = c is?

#### lightarrow

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #31 on: 17/09/2015 17:24:43 »
Tangential force. In modulus: F = (E/r)*β2

E = energy.
β = v/c

For a body with mass: E = mc2γ; γ = (1-β2)-1/2
For a body moving at c: β = 1.

Agreed, so as v→c, E → ∞ if m ≠ 0

And the radial force required to maintain circular motion of a massive body at v = c is?
Ehm, I wrongly wrote "tangential" force but it clearly was "radial" force. Sorry for the mistake and thank you to have noticed it!
I am correcting it.

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#### lightarrow

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #32 on: 17/09/2015 17:32:36 »
Tangential force. In modulus: F = (E/r)*β2

E = energy.
β = v/c

For a body with mass: E = mc2γ; γ = (1-β2)-1/2
For a body moving at c: β = 1.

About the energy needed to accelerate a body to light speed, see "E" up. For a photon you can write E = h*f if you like.

--
lightarrow
Did you know that in his 1905 paper on special relativity Einstein got the expression for the transverse mass wrong? Ohanian explains the error in his book Einstein's Mistakes located at http://www.newenglandphysics.org/other/Ohanian_Einstein_error_1905.pdf
http://www.newenglandphysics.org/other/Ohanian_Einstein_error_1905.pdf
Very interesting.
So, after all, Albert Einstein wasn't that "super mind" being we are used to think, but just a common person which makes the same kinds of mistakes you and me can make too

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#### alancalverd

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##### Re: What happens to an object moving in a circle at light speed?
« Reply #33 on: 17/09/2015 19:04:03 »
Ehm, I wrongly wrote "tangential" force but it clearly was "radial" force. Sorry for the mistake and thank you to have noticed it!
I am correcting it.

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lightarrow

Correction noted, and as I stated way back in this thread, F → ∞ if v → c and m ≠ 0. Glad we settled that.
« Last Edit: 17/09/2015 19:06:33 by alancalverd »

#### The Naked Scientists Forum

##### Re: What happens to an object moving in a circle at light speed?
« Reply #33 on: 17/09/2015 19:04:03 »