# Electromagnetic mass vs its velocity

• cryptoxicon
In summary, electromagnetic field possesses impulse and inertia, and has a certain amount of energy associated with it.
cryptoxicon
Dear friends,
I have a 5 minute presentation to give on the dependence of electromagnetic mass on its velocity for my physics class.
This could be a very broad question to answer, but all I ask is to direct me to some useful links.
I have troubles with that because I keep finding regular mass vs velocity rather than the mass of light or other forms of electromagnetic waves.
It would be nice to get a few general equations on this topic with a bit of theory behind it.

Also, any useful, substantial input on this topic from you guys will be highly appreciated :)

Alright I got a few things down. So there is a relativistic mass (mass in motion) and rest mass.
What exactly is electromagnetic mass?

cryptoxicon said:
What exactly is electromagnetic mass?
I was going to ask the same thing. What do you mean by electromagnetic mass? And velocity of what?

nasu said:
I was going to ask the same thing. What do you mean by electromagnetic mass? And velocity of what?

Well according to wikipedia, electromagnetic mass is a concept of mechanics, denoting as to how much electromagnetic energy is contributing to the mass of charged particles... So I think its safe to assume that electromagnetic mass is a mass of charged particles?

The question here is as follows:
How does this electromagnetic mass change relative to its velocity (the velocity of em mass)
Is it the same for any other mass? with a m = m0/sqrt(1-v^2/c^2)
where m = relativistic mass
m0 = rest mass
If this is the case, we are talking about the speed of an electron, which is very much like the speed of light...
If you need some more info on any other clarification of this question I will try to provide it to you.

cryptoxicon said:
Well according to wikipedia,

Please note that, in this forum, when you are asking for an explanation of something you found elsewhere, you must make a complete citation of the source so that someone else can go look at it. You have not cited an exact reference or link to where you found this.

"Electromagnetic mass" is a very unfamiliar terminology, and Wikipedia is not to be trusted all the time. I'm surprised that your school would accept such a source.

Zz.

ZapperZ said:
Please note that, in this forum, when you are asking for an explanation of something you found elsewhere, you must make a complete citation of the source so that someone else can go look at it. You have not cited an exact reference or link to where you found this.

"Electromagnetic mass" is a very unfamiliar terminology, and Wikipedia is not to be trusted all the time. I'm surprised that your school would accept such a source.

Zz.

My school most definitely doesn't support sources like wikipedia. I was just trying to make sense out of this "unfamiliar terminology" through any means possibly for my personal understanding.
After further research, I found more on electromagnetic mass, this time through a trusted source.
http://www.relativityoflight.com/Chapter17.pdf
(page 3)
Hope this helps to clarify my question further.

cryptoxicon said:
Alright I got a few things down. So there is a relativistic mass (mass in motion) and rest mass.
What exactly is electromagnetic mass?

It's a somewhat historical concept, although it's still discussed in the context of "charged particles".

http://en.wikipedia.org/wiki/Electromagnetic_mass

There you find also some reputable sources, such as
Feynman's lectures on physics, Volume 2, "Chapter. 28: Electromagnetic mass"

Janssen, Michel & Mecklenburg, Matthew
http://philsci-archive.pitt.edu/archive/00001990/

For a modern interpretation also in relation to quantum mechanics, see Rohrlich:
"The dynamics of a charged sphere and the electron", American Journal of Physics 85 (11): 1051–1056, 1997
See also his book: "Classical charged particles" (2007)

Regards

Histspec said:
It's a somewhat historical concept, although it's still discussed in the context of "charged particles".

http://en.wikipedia.org/wiki/Electromagnetic_mass

There you find also some reputable sources, such as
Feynman's lectures on physics, Volume 2, "Chapter. 28: Electromagnetic mass"

Janssen, Michel & Mecklenburg, Matthew
http://philsci-archive.pitt.edu/archive/00001990/

For a modern interpretation also in relation to quantum mechanics, see Rohrlich:
"The dynamics of a charged sphere and the electron", American Journal of Physics 85 (11): 1051–1056, 1997
See also his book: "Classical charged particles" (2007)

Regards

Thank you for your good answer. I have been reading some more on this stuff, and from what I can understand, electromagnetic field has an impulse, as well as inertia. The formula for impulse is derived from 3 equations: F=ma, p=mv, and F= uS. The last one doesn't look as familiar, but apparently its the force from the pressure exerted by the field, where u is pressure, S is surface area. By writing Newton's second law in a differential form, F = m(dv/dt) and taking the derivative of the classical impulse formula: dp/dt = m(dv/dt), we substitute:
dp = Fdt
This is where the pressure formula comes in:
dp = uSdt, and after some incomprehensible to me substitutions, we get: p = W/c, where W is energy of the field and c - speed of light.
So if electromagnetic field possesses these two properties of having impulse and inertia, it is wise to assume that it has a mass too. If I understood correctly, this kind of mass is electromagnetic mass?

## 1. What is electromagnetic mass?

Electromagnetic mass is a concept in physics that describes the increase in mass of an object as it moves at high speeds, approaching the speed of light. This increase in mass is due to the object's interaction with the electromagnetic field.

## 2. How does the velocity of an object affect its electromagnetic mass?

The greater the velocity of an object, the greater its electromagnetic mass will be. As an object approaches the speed of light, its electromagnetic mass approaches infinity.

## 3. Is electromagnetic mass a real physical phenomenon?

Yes, electromagnetic mass has been confirmed through experiments such as the famous Michelson-Morley experiment. It is also a crucial component in various theories, such as Einstein's theory of relativity.

## 4. Can electromagnetic mass be observed in everyday life?

No, the effects of electromagnetic mass are only noticeable at extremely high speeds, such as those near the speed of light. In everyday life, the increase in mass due to electromagnetic interaction is negligible.

## 5. How does electromagnetic mass differ from inertial mass?

Electromagnetic mass is a type of inertial mass, which is the resistance an object has to changes in its state of motion. However, while inertial mass is constant regardless of an object's velocity, electromagnetic mass increases as the velocity of an object increases.

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