All Questions
Tagged with electromagnetism forces
525
questions
44
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5
answers
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Can the Lorentz force expression be derived from Maxwell's equations?
The electromagnetic force on a charge $ e $ is
$$ \vec F = e(\vec E + \vec v\times \vec B),$$
the Lorentz force. But, is this a separate assumption added to the full Maxwell's equations? (the ...
- 1,342
3
votes
2
answers
8k
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What is the force between two magnetic dipoles?
What is the force between two magnetic dipoles?
If I have two current loops parallel to each other with currents $I_1$ and $I_2$ and radii $R_1$ and $R_2$ a distance $z$ from each other, what is the ...
- 141
6
votes
5
answers
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Work done by the Magnetic Force
The magnetic part of the Lorentz force acts perpendicular to the charge's velocity, and consequently does zero work on it. Can we extrapolate this statement to say that such a nature of the force ...
2
votes
3
answers
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How does one calculate the force applied on an object by a magnetic field?
I've tried very hard to find an answer to this question, and every path leads me to an abstract discussion of fundamental forces. Therefore, I will propose two very specific scenarios and see if they ...
- 325
15
votes
2
answers
20k
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What is the cause of the normal force? [duplicate]
I've been wondering, what causes the normal force to exist?
In class the teacher never actually explains it, he just says "It has to be there because something has to counter gravity." While I ...
- 253
2
votes
3
answers
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What was meant by the 'ponderomotive force' as understood by Minkowski?
Skimming through Minkowski's famous 1907 paper, he uses the term ponderomotive force.
What does he mean by this?
- 3,108
3
votes
2
answers
9k
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Why exactly does current carrying two current wires attract/repel?
When to parallel wires carrying currents in same direction $I_1$ & $I_2$.
The MIT Physics Demo Forces on a Current-Carrying Wire this video demonstrates that effect.
My question is, why exactly ...
- 7,335
1
vote
2
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Pollen Particle Attracted to TV due to Which Force?
A pollen particle has no charge so I cannot understand how the Lorentz force $\bar{F} = q \bar{E} + q(\bar{v} \times \bar{B} )$ could explain the event. I speculated that it is because of the electric ...
- 609
4
votes
1
answer
172
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3 current loops with non-conservation of momentum, when one specifically considers SIGNs
Thought experiment I.
Consider two loops of wire, 2 small dipoles B and C , with a common axis z (facing each other) and (say) 30 cm apart B to C. At the speed of light, information (including a ...
- 101
3
votes
4
answers
549
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existence of other forces obeying inv square law
Is there any restriction in what we know of physics to the existence of other type of forces that obey the inverse square law in 3 dimensions.
I mean other than electromagnetic and gravitational.
...
- 627
0
votes
1
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1k
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How is a magnetic field translated into physical force?
Related to this question
Where do magnets get the energy to repel?
If I have a magnet repelling another, eg one in my hand, the other being pushed along the desk, how do the each of the magnet's ...
- 101
13
votes
9
answers
57k
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What's the core difference between the electric and magnetic forces?
I require only a simple answer. One sentence is enough... (It's for high school physics)
- 245
122
votes
10
answers
17k
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How can I stand on the ground? EM or/and Pauli?
There is this famous example about the order difference between gravitational force and EM force. All the gravitational force of Earth is just countered by the electromagnetic force between the ...
- 1,321
8
votes
3
answers
2k
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How can we make an order-of-magnitude estimate of the strength of Earth's magnetic field?
The source of Earth's magnetic field is a dynamo driven by convection current in the molten core. Using some basic physics principles (Maxwell's equations, fluid mechanics equations), properties of ...
- 53.2k
26
votes
6
answers
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Where do magnets get the energy to repel?
If I separate two magnets whose opposite poles are facing, I am adding energy. If I let go of the magnets, then presumably the energy that I added is used to move the magnets together again.
However, ...
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