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

Apr2211 05:26 AM
ZapperZ

1 
47,683 
Consider many same particles are moving randomly in a constant pressure and constant temperature box. The average...

Jan809 04:08 PM
KFC

2 
2,785 
There are two compartments, each has half volume of the total volume, separated by an insulating partition. The whole...

Jan509 09:19 PM
Mapes

2 
5,406 
In my text of classical mechanics, it reads: for all relations
f(q_1, q_2, \cdots; \dot{q}_1, \dot{q}_2, \cdots, t)...

Jan709 11:22 PM
IPart

2 
3,113 
Hi Folks,
It seems there are some differing opinions in my office with respect to the following.
If one is to...

Jan509 07:42 PM
Q_Goest

2 
4,733 
New Member  I have to say  This site is amazing Great find, Been reading for hours now and I have come to a...

Jan609 09:24 AM
Naty1

2 
1,140 
something i cant grasp is
why is it that when you lift one end of a log and the center of mass is raised a certain...

Jan709 06:03 AM
Rajini

2 
1,537 
Hi I was wondering if I took two peices of copper and held them together then ran a current through the connection...

Jan709 01:08 PM
berkeman

2 
1,688 
In thermodynamics, we always need to use exact differential relations to find the so called Maxwell relations. For a...

Jan1309 10:47 AM
jojo12345

2 
1,090 
Please forgive my ignorance on what may be simple topics for most of you. I'm just trying to get my head conceptually...

Jan1109 10:27 AM
marietta_ken

2 
1,136 
I've often heard physicists say that the relative weakness of gravity is 'one of the greatest unsolved problems in...

Jan1309 07:51 AM
Andy Resnick

2 
2,884 
How can one determine the amplitude, frequency and period of an amplitude? this is not homework, i was just curious,...

Jan1309 03:02 AM
Thaakisfox

2 
21,466 
Hi all, there are a few questions regarding the incandescent light bulb, which I believe are rather elementary, but...

Jan1309 12:13 PM
cabraham

2 
18,574 
Hi,
I am working on a problem with a free hanging mass attached to a spring and damper in parallel. I believe my...

Jan1409 11:01 AM
skeleton

2 
5,622 
Do sudden changes occur in thermodynamic systems? If so, when do they occur and why?
More specifically: When a...

Jan2709 08:53 PM
Sedunov

2 
1,209 
Hi,
This is not homework but out of curiosity. On a diving board where are the points where stress is applied?...

Jan1609 11:31 AM
cthor

2 
1,954 
Suppose we have lots of forces F1,F2,F3 etc acting at a point. Then pressure would be the magnitude of vector sum...

Jan1709 12:54 PM
tinytim

2 
877 
 THREE MAGNETS (Ndipolebody problem) 
imagine 3 bar magnets sitting on a table randomly spaced. they are...

Jan1809 03:08 AM
Sione

2 
1,031 
A common exposition of Hamiltonian mechanics (e.g., Goldstein's Classical Mechanics) is to start with the action
...

Jan1809 08:05 PM
pellman

2 
2,253 
http://en.wikipedia.org/wiki/Electromagnetic_waves
Please navigate to this link about electromagnetic waves. Scroll...

Jan2109 06:28 AM
fasa

2 
4,822 
Consider a problem where a tank holds compressed natural gas, compressed to approx. 250 times atmospheric conditions....

Jan1909 12:36 PM
boka33

2 
7,286 
I have a question about the Lagrange Multiplier method used to derive the Boltzmann distribution. I'm following the...

Jan2009 07:38 AM
Peter Forbes

2 
7,072 
I want to calculate the temperature on the outside of a pipe which has a heated fluid flowing through it. If I know...

Jan2309 06:14 PM
henxan

2 
7,952 
I got a thought on this strange hypothetical question. We differentiate between matter and anti matter based on...

Jan2309 07:13 AM
spidey

2 
2,799 
I've "derived" the first Maxwell equation of the divergence of the Efield starting at the Coulomb force of a point...

Jan2409 01:58 AM
dx

2 
4,406 
The vector potential can be expressed in the following way:
∇^2 Ay∂/∂y (∇∙A)=μJy
(Here only taking y...

Feb209 08:54 AM
muscaria

2 
2,539 
EDIT  I posted this here because I figured its more of a conceptual problem than a HW problem, but if people see...

Jan2609 11:38 PM
sganesh88

2 
1,064 
Is E=0 in super conductor also? I read in the below site that static electric field goes some depth into super...

Jan2809 09:46 AM
spidey

2 
3,204 
A system with one particle in one dimension x, momentum p, and hamiltonin H(x,p). Hamilton's principal function...

Jan2909 10:11 AM
pellman

2 
745 
how do u calculate what one circle does when it collides with another circle at a specific point on a specific...

Jan3109 06:44 PM
cam875

2 
1,870 
when two electro magnets are coiled the same and same direction of current are placed S to S so they repell... is the...

Feb109 11:12 AM
Gdarnall

2 
1,630 
Revising my old university lectures, I have encountered the famous law of magnetic field around a closed loop:
...

Feb209 01:04 PM
valjok

2 
1,440 
I remember reading before that hydrogen gas is "transparent" to gamma rays. What does this mean? I know it has...

Feb409 12:21 PM
QuantumPion

2 
1,330 
Hey I am confused about the direction of reaction force..
When a ball is on a vertical track at the bottom most of...

Feb609 05:10 AM
Doc Al

2 
1,278 
Hello,
I would like to know if there are experimental tests of the Equivalence Principle in the realm of...

Feb609 07:09 AM
lalbatros

2 
1,140 
Till now...has anyone made such an arrangement that converts an applied force to 90+ degrees completely without use of...

Feb909 11:17 PM
dE_logics

2 
1,100 
I read about electrons and positrons free fall within a superconducting cylinder, in this book (p 105):
...

Feb609 08:27 AM
lalbatros

2 
1,285 
Suppose I prepare a liquid whose density is equal to the average density of my body.
Hence when I am completely...

Feb1209 07:40 AM
Andy Resnick

2 
1,066 
Title says all,
why clouds are up? have the air more density than water?
Thanks!

Feb1409 04:46 PM
LURCH

2 
1,740 
Can anyone verify that I'm thinking about this situation correctly:
among cyclists, there exists a thing called a...

Feb1509 09:36 PM
atyy

2 
1,012 
Hello,
In this problem: http://www.physics.harvard.edu/academics/undergrad/probweek/prob1.pdf
Two balls are...

Feb1509 04:03 PM
darkSun

2 
1,358 