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

Apr2211 05:26 AM
ZapperZ

1 
47,912 
How can life be compatible with the second law of thermodynamics?
Here is how. Life is a selforganized system. A...

Aug2814 10:57 AM
Shyan

1 
151 
A rope is wrapped around a pole with one end attached to a large object and the other end pulled with a tension T. ...

Aug2814 06:27 AM
DeltaČ

3 
176 
I am programming an addon for a space game/simulation (Kerbal Space Program) and I am looking for some help with a bit...

Aug2814 03:07 AM
A.T.

7 
208 
The only force really considered in classical mechanics is gravity. And yet, we often have problems involving...

Aug2714 11:35 PM
DeltaČ

2 
200 
For the classic Lenz law demonstration using a neo. magnet dropped down a copper pipe, is the magnetic force generated...

Aug2714 04:52 PM
Philip Wood

11 
880 
I came across this article was incredibly interested. I've read the paper and the material was completely over my...

Aug2714 01:55 PM
Drakkith

1 
171 
Hi PhysicsForums,
I was wondering if this youtube was a correct representation of a photon traveling through space...

Aug2714 12:18 PM
jlyu002@ucr.e

6 
265 
Hello,
I am at present analyzing the electromagnetic interaction of a layer of paritcles in air when illuminated...

Aug2714 10:53 AM
Karthiksrao

0 
126 
Many of you are familiar with the catapult launched profile fuselage gliders that are sold in hobby stores. Since...

Aug2714 06:04 AM
A.T.

16 
1,042 
In almost every textbook I have seen, pressure is said to be one of the most important state variables of a...

Aug2614 06:11 PM
Chestermiller

9 
213 
Hi Guys! I have a, rather general, question regarding the nature of magnet repulsion.
When two opposite poled...

Aug2614 05:29 PM
Bobshark

2 
143 
According to d'Alembert's Principle, the virtual work done by constraint forces must be zero.
I have a few things...

Aug2614 04:26 PM
Greg Bernhardt

1 
242 
Hello everyone, I was recently creating two different types of plasma for a Science Fair, one created from ionised...

Aug2614 10:37 AM
Simon Bridge

7 
260 
Hi all, I'm new to the forums (in posting at least!). I recently graduated with a B.S. in Applied Physics, and have...

Aug2614 08:49 AM
Andy Resnick

9 
280 
Hello PF'ers,
Why is it that two lightbulbs produce twice as much brightness as a single lightbulb would? If we...

Aug2614 08:24 AM
ViolentCorpse

4 
207 
I want to construct 5 sided dice in the shape of a squarebased pyramid.
When rolled, I want the die to have equal...

Aug2514 09:09 PM
Haborix

12 
385 
hi,
I'm a student and i have an electromagnet and a bar magnet paced head on coaxially and i want to calculate the...

Aug2514 07:16 PM
Meir Achuz

32 
851 
I cannot seem to visualize how this compression and rarefaction occurs for example when I clap my hands, I know I move...

Aug2514 07:09 PM
hongiddong

4 
204 
Hey!
I need to calculate the electric field on the axis of a circular plate of radius a with the following charge...

Aug2514 03:24 PM
loops496

2 
145 
Hello,
I am having trouble understanding collision frequency in following discussion from Kubo,...

Aug2514 08:46 AM
AirTycoon

2 
127 
Hello,
I am a PhD student in chemistry, and need to determine the pressure of a reaction to be carried out
I...

Aug2414 11:32 PM
Chestermiller

5 
204 
I am having trouble wrapping my head around the idea of a piston/cylinder type arrangement where the piston has a...

Aug2414 05:54 PM
ullrtech

7 
270 
I know that delta h(Enthalpy) is heat and it is also the total kinetic energy of the system.
Temperature is the...

Aug2414 02:13 PM
Andrew Mason

11 
417 
While deriving lagrangian equation using D'Alembert's principle, in Goldstien, they defined a variable called "virtual...

Aug2414 10:08 AM
USeptim

1 
214 
My question relates to entropy generation in a closed system
ΔS=dQrev/T for a reversible process
ΔS=dQ/T + Sgen for...

Aug2414 09:54 AM
Chestermiller

12 
262 
Just read in Taylor that in general the kinetic energy can depend on position as well as velocity. I believe him, but...

Aug2414 09:47 AM
USeptim

9 
326 
How magnetic field associate with mass........
from the experiment we know that this is due to electric charge........

Aug2414 06:39 AM
ChrisVer

3 
253 
We know that a steam power plant is basically a heat engine with steam as the working fluid.
According to the...

Aug2314 11:35 PM
Soumalya

8 
1,017 
when a magnetic field exert force on a moving charge the work done by it is 0.But bar magnet do work.And i read that...

Aug2314 04:52 PM
DaleSpam

83 
2,134 
I am not sure if this is the right forum for this question, but I arrived at the question while studying the principle...

Aug2314 03:18 AM
A.T.

9 
284 
In my theoretical mechanics class, we went over some very basic conservation laws (namely momentum) and talked about...

Aug2214 03:37 PM
Orodruin

1 
178 
Hi all,
I am preparing for my "second chance exam" in analytical mechanics.
It is a graduate course i.e. based on...

Aug2214 11:38 AM
samalkhaiat

2 
235 
Divergence of electric field is 0 for the field produced by a point charge at origin at points other than origin is 0;...

Aug2214 12:43 AM
DeltaČ

1 
228 
In vector form,
L=Iω.
I am trying to show that for a point particle, this reduces to L=rxp, but am getting an...

Aug2114 06:05 PM
jtbell

1 
164 
I was going through "Engineering Thermodynamics" by Cengel & Boles studying exergy analysis of a closed(non flow)...

Aug2114 01:36 PM
Soumalya

3 
200 
For a uniform, hollow cylinder, why is this derivation wrong?
M = mass of whole solid cylinder
m = mass of missing...

Aug2114 12:42 PM
BrainSalad

3 
197 
I'm given an expression for the pressure of air with height z, as
P(z)=P(0)e^{(mgz/k_bT)}
Where m is the...

Aug2114 11:09 AM
Greg Bernhardt

1 
238 
Hello Forum,
Resolution is an angular distance (measured in fractions of an 1 degree angle). The lower the...

Aug2114 09:52 AM
fog37

3 
210 
I hope this is posted in the correct thread.
When I was still in my physics class, we learned that a loop of wire...

Aug2114 02:06 AM
Simon Bridge

15 
370 
According Pascal law we get force high and low to the applying force.....why fluid not behave like ideal solid body...

Aug2114 02:02 AM
rcgldr

15 
277 