
Before posting anything, please review the Physics Forums Global Guidelines.
Again, for some odd reason, people...

Apr2211 05:26 AM
ZapperZ

1 
47,906 
Basic electrostatics (as I've seen it presented) usually starts off with an implicit \mathbf{F} = q q_2...

Aug2708 07:31 AM
PhilDSP

28 
7,127 
How can I prove that newtonian potential of nbody problem is homogeneous function of order 1?
Please help!
...

Aug2708 04:56 AM
AmateurNS

0 
1,399 
What is the volumetric heat capacity of Erbium? I've read it's the highest of any material at a temperature between 18...

Aug2708 03:03 AM
NJV

0 
1,303 
Hello,
I am trying to measure diameter of the hole in my equipment by doing the photography with digital camera.
...

Aug2608 09:11 PM
Andy Resnick

2 
2,297 
Hi everyone,
I have a uniform electric field in which I place an object. I have read that the electric potential...

Aug2608 05:35 PM
granpa

6 
1,621 
suppose you have a system
Ma + Kx = 0 for some nxn matricies M and K
assuming a harmonic solution of the form a...

Aug2608 03:31 PM
JohnSimpson

1 
3,871 
Does anyone have an equation that describes the magnetic moment of a solenoid that does not actually use number of...

Aug2608 09:13 AM
Kydharis

5 
4,553 
How can I get the central force law by using orthogonal transformation of position vector, x=Ar where A is an...

Aug2608 07:31 AM
AmateurNS

1 
1,510 
In classical mechanics (also in QM I guess), the fundamental laws of conservation (energy, momentum and angular...

Aug2608 04:52 AM
james77

7 
2,418 
After having set up a trebuchet in my back yard, I decided it would be a fun excersise to predict the range of the...

Aug2508 01:44 PM
kingbabi

2 
3,327 
Hi, so glad to be here. This is my first posting. I'm just a 61 yearold dummy, so please help!
If a rubber ball is...

Aug2508 10:30 AM
Llewlyn

3 
1,656 
I've been fascinated by the idea of inductive coupling for a long time, so this weekend I decided it was finally time...

Aug2408 07:30 PM
trustfarm

0 
8,535 
Hi.
Wich experiments show that an electromagnetic wave is a wave?
And what kind of wave? How i think of it? Sure...

Aug2408 04:40 AM
granpa

43 
7,225 
force between two charges is it electric force or electromagnetic force?
And force between the atom nucleus and the...

Aug2408 03:00 AM
mite

2 
1,231 
An antenna behaves like an RCL circuit.
The R is the radiation resistance corresponding to energy actually radiate....

Aug2308 06:36 PM
fisico30

2 
3,757 
Hello:
In Classical mechanics, the lagrangian of a system is defined as the kinetic energy minus the...

Aug2308 05:55 PM
Troponin

1 
1,241 
I'm trying to solve the question b) in this linkhttp://i36.tinypic.com/2h3wmtx.jpg
My reasoning is
dK = dm v^2...

Aug2308 10:12 AM
Mårten

1 
1,552 
Hi this is my first post here so I hope it's in the right place!
I am doing a computer course and we are using...

Aug2208 09:58 PM
Andrew46826

0 
1,962 
Dear All,
Please excuse my ignorance of physics. According to some Russian research 1 mW of microwave radiation could...

Aug2208 07:18 PM
mgb_phys

3 
1,564 
Hello, please forgive my ignorance. I need help coming up with a formula I can't seem to find on the internet. ...

Aug2208 02:57 PM
clem

1 
1,287 
Starting with the equation of motion kx = ma , it is said that integrating this with respect to x gives the equation...

Aug2208 11:18 AM
Narcol2000

2 
2,017 
How would I go about calculating the resonant frequency of a tube with a slit cut out from its length. I'm looking for...

Aug2208 11:04 AM
phdpe

0 
1,022 
prove this claim in landau ...
Closed systems have lagrangians which do not contain time explicitly

Aug2208 08:33 AM
pardesi

0 
1,245 
It is a wellknown consequence of classical electromagnetism that any accelerating charged particle must radiate (not...

Aug2108 05:35 AM
Shooting Star

24 
5,415 
Hello,
I want to know how long time a running runner needs to reach a point, when he is initially running in the...

Aug2108 03:03 AM
ManuTOO

0 
1,219 
Hi.
What is a ¨charge¨ ? What does it mean that an electron has a negative charge?
What is modified in particle...

Aug2008 10:56 PM
Defennder

1 
973 
Im trying to calculate energy of the turbines to lift an airplane , by this way, calculating potential energy...

Aug2008 10:49 PM
rcgldr

6 
1,769 
According to Coulomb's law we have that the force between two charged particles could be described by
(1)~~~F = k...

Aug2008 03:59 PM
Mårten

35 
4,398 
So I was doing this one problem in which there is a sphere of radius r and charge density row and there is a spherical...

Aug2008 10:21 AM
atyy

15 
2,598 
Dear Experts,
Are there any effects that could be induced with electrity in a microgravity environment that can...

Aug2008 07:29 AM
Andy Resnick

1 
1,375 
I am doing an experiment on the pendulum, and i wanted to do something on the damping, i understand a little as i have...

Aug2008 06:29 AM
amppatel

3 
2,159 
I have a statics question. In my book under a picture it says.
"To save material the beams used to support the...

Aug2008 02:18 AM
rdbateman

5 
1,669 
Hello, good afternoon.
I would ask you for the help of my work in physics.
As you well understand, I'm not North...

Aug1908 01:21 PM
azimovas

6 
2,716 
hi..i'm an undergraduate student.i'm working on my final year project. i've been looking for the permittivity and...

Aug1908 11:59 AM
antenna

2 
1,252 
Hey all,
Just a bit of background info:
I'm doing an investigation on low temperature plasmas and one of the...

Aug1908 08:40 AM
DaleSpam

1 
2,296 
My boss and i were considering he following problem (see attached image):
2 unequal masses rotate an equal...

Aug1908 08:36 AM
jasc15

3 
5,306 
I have posted this question earlier also. But i am changing my sentences a bit.
This is regarding conservative and...

Aug1808 10:15 AM
i_island0

16 
1,816 
is there another way of considering the specific heat capaciaty of a material (many gas) other than with respect to...

Aug1808 03:56 AM
gemt

4 
1,492 
Suppose an object is suspended above the Earth, then released. It immediately accelerates to 32.2 f/s^2. There should...

Aug1708 06:35 PM
TVP45

55 
8,397 
Hello,
I've come up with a simple, imaginary situation that bugs me. Could someone help resolve my confusion?
...

Aug1708 05:09 PM
DaleSpam

2 
1,297 