# Are charge and escape velocity related?

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#### jeffreyH

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##### Are charge and escape velocity related?
« on: 04/05/2015 10:31:00 »
Can someone verify that answer number 8 is actually true in the following forum post.

http://physics.stackexchange.com/questions/61261/do-objects-have-energy-because-of-their-charge

It seems a little dubious to me.
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#### evan_au

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##### Re: Are charge and escape velocity related?
« Reply #1 on: 04/05/2015 12:24:29 »
Quote
As you increase the charge the escape velocity decreases...
I think this description (and the equation provided) is for two objects with the same charge sign (ie both positive, or both negative).

On the atomic scale, you can almost ignore mass (M=0), and so the value inside the square root is negative. This can often be read as "not a real solution". ie when you put two protons close together, they repel each other, and you don't need to give them any initial velocity for them to vigorously escape "to infinity".

However, if you have two charges of opposite sign (ie a positive and a negative charge), the sign of the charge contribution reverses, and there is a real escape velocity; increasing the charge increases the escape velocity.

Of course, if you are talking about a proton and an electron, quantum theory dominates, and the concept of an "escape velocity" gets a bit rubbery...

As for the remainder of the article; whether you could calculate the mass of a neutron or a proton from the charges of the constituent quarks: I will leave that to others for comment...

#### jeffreyH

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##### Re: Are charge and escape velocity related?
« Reply #2 on: 04/05/2015 12:35:02 »
I see now. As for proton and neutron masses I haven't a clue.
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#### jeffreyH

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##### Re: Are charge and escape velocity related?
« Reply #3 on: 04/05/2015 12:43:43 »
Thinking about it wouldn't the following give the mass?

$$M=\frac{2G}{rv^2}+\frac{2r}{Q^2}$$

But good luck in solving it.

CORRECTION: $$M=\frac{2G}{rv^2}+v^2\frac{Q^2}{2r}$$
« Last Edit: 04/05/2015 12:56:23 by jeffreyH »
Fixation on the Einstein papers is a good definition of OCD.