All Questions
15
questions
122
votes
10
answers
17k
views
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
78
votes
4
answers
11k
views
How exactly is a normal force exerted, at the molecular level?
I've been surfing the web for quite a while, finding the answers I would need, but couldn't find a convincing one. First of all I need to remind you that this a very long/continuous question, so ...
user226894
3
votes
3
answers
397
views
Detect reaction force to Lorentz force
If a charged particle is deflected in a magnetic field due to some magnet, is there any experiment that shows (or measures) the opposite reaction force (due to Newton's third law) on the magnet?
- 737
2
votes
3
answers
426
views
A broader view on contact forces
I am aware that all the contact forces we experience like tension, friction, normal reaction, et cetera are complex manifestations of the fundamental forces which are gravitational forces, ...
- 1,147
15
votes
2
answers
20k
views
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
6
votes
1
answer
1k
views
Resemblance between Coriolis force and magnetic part of Lorentz force
If we interchange velocity with charge and omega that is rotation of a system with $B$, magnetic field, we get the same thing. Is there any deeper meaning to this same mathematical form?
- 1,803
3
votes
2
answers
507
views
Does constraint for speed of Electric and magnetic fields violates Conservation of momentum or Newton's third law?
I'm just a beginner so bear with me. Consider two frames at rest wrt to each other separated by distance enough for light to take a minute or so. At a given instant we create two large dipoles by some ...
- 31
57
votes
4
answers
5k
views
Is there an underlying physical reason why the Coriolis force is similar to the magnetic component of the Lorentz force?
I couldn't help but notice that the expression for the magnetic component of the Lorentz force,
$$\mathbf F = q\,\mathbf v \times \mathbf B\,,$$
is very similar in its mathematical form to the ...
- 2,463
32
votes
6
answers
6k
views
If I push someone, what fundamental force do I create?
According to Wikipedia, all forces can be decomposed to four fundamental forces: gravity, electromagnetism, strong interaction and weak interaction.
When I push someone, this generates a force. Which ...
- 1,440
26
votes
14
answers
4k
views
Explaining how we cannot account for changing acceleration questions without calculus
For context, I am a high school physics teacher.
I am teaching students about the basics of electromagnetic force between two point charges. The equation we use is $F=\frac{kq_1q_2}{r^2}$.
This gives ...
4
votes
1
answer
172
views
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
4
votes
2
answers
2k
views
Is Newton's law really invariant under Galilean transformation (for velocity-dependent Lorentz force)?
Consider the motion of a charged particle of charge $q$ and mass $m$ from two different inertial frames $S$ and $S'$ connected by Galilean transformation equation ${\vec r}'={\vec r}-{\vec V}t$. This ...
- 11.8k
1
vote
2
answers
57
views
Possiblity of predicting behavior of system when properties described as functions over space?
Suppose I am given a system that consists of a distribution of charged particles(which are all over space and are point-charges). They are described by a set of functions instead of variables. These ...
- 121
1
vote
3
answers
433
views
Does a force perpendicular to the direction of movement not do work?
I have read that since the magnetic force acting on moving charge is always perpendicular to the velocity of moving charge, the field is not doing any work on the charge.
However, if a ball rolling ...
- 261
1
vote
1
answer
516
views
What is the difference between the contact force and Tension?
Both are electromagnetic forces, yet why does tension pull whereas the contact force pushes?
It is not like a rope has some material which can pull, if a slack rope is just kept on a table then it ...
- 451