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

Apr2211 05:26 AM
ZapperZ

1 
45,678 
A house with AC in a hot climate should be painted white (or covered with mirrors) to reduce absorption of light from...

Sep2109 06:09 PM
ejensen6

10 
2,857 
Hello,
I am stuck on the coriolis force. If an object is dropped how do I get the eastward deflection when looking...

Sep2109 04:41 PM
Cleonis

2 
1,593 
What does it mean to say that the fundamental relation of thermodynamics is homogeneous firstorder?
I struggle...

Sep2109 03:10 PM
Count Iblis

5 
2,122 
I tried to use Lagrangian and Hamiltonian to solve 1D elastic collision, but I got nothing but constant velocity...

Sep2109 12:18 PM
kof9595995

6 
2,329 
Hello,
I wonder if there is a common origin to the 'virial theorem' by Clausius and the 'virial expansion' or...

Sep2109 06:42 AM
DaTario

1 
778 
For some reason I have been extremely curious of how Newton derived his mathematical law for gravitation. You know
...

Sep2009 08:55 PM
alxm

1 
2,978 
Why is it that the equation for work done to stretch a spring is
W = 1/2k(x22x12)
while the work done by a...

Sep2009 08:26 PM
woodie37

11 
13,160 
Say i have a capacitor and i supply it with a voltage V and after that it has charge density sigmainitial on each...

Sep2009 07:17 PM
sophiecentaur

3 
740 
Imagine two small metal spheres of equal mass and size moving at the same speed in opposite direction collide with...

Sep2009 12:31 PM
mahela007

3 
1,981 
I am having a lot of trouble conceptually understanding this issue in Lagrangian mechanics:
I have an airfoil which...

Sep2009 02:37 AM
thrillhouse86

0 
908 
In this problem we assume that the photon mass is m > 0. We take a conducting sphere of radius R and put a charge of...

Sep1909 09:58 PM
Count Iblis

17 
3,586 
Is there a derivation for the classical electrodynamic Lagrangian? I have taken a look at a few textbooks that I have...

Sep1909 09:46 PM
Count Iblis

4 
2,081 
Hi,
I am solving the following nonlinear dynamical system using Energy Balance Method (EBM*). My intention is to...

Sep1909 05:38 PM
DaleSpam

3 
752 
Can any one help me define viscosity and the newtons relations to define viscosity
Surely am having a confusion as...

Sep1909 08:35 AM
Godwin Kessy

4 
3,855 
Here is a statement about the Liouville's theorem in my textbook:
"Because we are unable to discuss the details of...

Sep1909 07:53 AM
kof9595995

2 
1,474 
Before I start studying the relativity theories, I have to grasp this concept:
Suppose two cars are moving with...

Sep1909 02:07 AM
mjcguest

5 
684 
Hi,
I need some help in writing the Hamiltonian function for the following dynamical systems.
1) u''+u=A...

Sep1809 11:15 PM
dekarman

2 
1,335 
Hi,
I understand that force due to an electromagnetic field on a surface can be calculated by
F = \oint {T . n...

Sep1809 10:16 PM
TMM

3 
4,959 
I have a stereo setup with a subwoofer. Sometimes, if my laptop is plugged in close by or in the same outlet, the...

Sep1809 05:47 PM
berkeman

1 
1,128 
This example is highlighted in the Wikipedia definition of perpetual motion.
Machines which are claimed not to...

Sep1709 10:26 PM
Integral

4 
2,828 
Consider a frictionless plane. A particle of known mass and velocity (say a lump of clay) strikes a uniform rod (for...

Sep1709 07:53 PM
GluteusMedius

4 
1,348 
I am having problems defining what equations to use to find internal energy, heat, work, enthalpy. for a ideal gas in...

Sep1709 05:20 PM
bob2k6

0 
524 
The law of conservation of momentum states that all momentum is conserved in a collision. Momentum is defined as p =...

Sep1709 04:17 PM
sugaJ

2 
3,624 
(Not sure if anyone has asked this before)
This idea might be a little vague and I'm sure there is a simple solution...

Sep1709 01:36 PM
A.T.

2 
651 
Does statistical mechanics predict any relation between macroscopic observable variables (if I cannot make any...

Sep1709 01:03 PM
Gerenuk

0 
860 
suppose a body is at rest say on earth surface, does it posses potential energy?

Sep1709 10:33 AM
HallsofIvy

1 
544 
Hi,
What happens to the fluid in a cylinder that is spinned around it's central axis? Would it matter if there...

Sep1709 06:35 AM
CFDFEAGURU

6 
2,841 
The second law of thermodyanics states that heat cannot flow from a colder region of space to a hotter region; When...

Sep1709 01:20 AM
monty37

10 
1,185 
Does anyone happen to have the equations for angular mass (moment of inertia; axial and transverse) of a conical...

Sep1709 12:33 AM
tuoni

0 
752 
This is just a conceptual think I have been thinking about. Hopefully I am not just missing something obvious.
...

Sep1609 10:27 PM
russ_watters

1 
599 
basic E and M from purcells:
A change in magnetic field with respect to time, will induce a current in a...

Sep1609 09:39 PM
ideasrule

6 
729 
Does anyone know how either Lienard or Wiechert justified the (1v/c) factor that appears in their potential formula...

Sep1609 03:05 PM
clem

3 
971 
Hi,
Can anyone give me any information on where i could find information on the emissivity of a gas, particulally...

Sep1609 03:04 PM
Bob S

2 
6,966 
I was reading the Feynman lectures, on the parts that deal with optics, and he explains diffraction in a very...

Sep1609 04:11 AM
WiFO215

4 
790 
I was hoping people might be able to provide some insight into the following fairly basic scenario (not...

Sep1509 07:32 PM
hd90001

0 
1,273 
Suppose you have a line charge Q along the x axis from +a to a. Simple integration should give the potential at any...

Sep1509 04:16 PM
xanadu

3 
1,151 
Suppose that, a sudden current pulse has been generated (by means of a Magnet) in a SuperConducting Loop (or coil)....

Sep1509 12:00 PM
Bob S

20 
4,401 
I was in my Electrodynamics lecture last week, still working the Laplacian and Poisson equations, when we discussed an...

Sep1409 03:51 PM
makhoma

1 
663 
Hello all,
Sorry for the long post. Skip to the line for the relevant part.
As a longtime ultimate frisbee...

Sep1409 01:59 PM
Kricket

4 
1,785 
Please look into this site
http://knol.google.com/k/alexbelov/paradoxofclassicalmechanics2/1xmqm1l0s4ys/9#
...

Sep1409 07:35 AM
Doc Al

1 
1,589 