The aim of this thread is to highlight recent (as in within the past 3 months) noteworthy physics papers that have...

Apr814 10:13 AM
ZapperZ

166 
159,829 
Before posting anything, please review the Physics Forums Global Guidelines.
If you are seeking help with a...

Apr2211 05:27 AM
ZapperZ

2 
63,487 
Hi all,
Lets suppose we have a sphere.
This sphere has density of \rho(r) from 0 to the sphere's final radius R.
...

Oct1813 11:51 PM
elis02

2 
445 
Hi there,
I am trying to understand the physics acting on a discus thrower, namely at their feet when they throw a...

Oct1813 08:22 PM
imanator

5 
460 
I know that this question may sound silly , but I really can't get the difference between intensity and density in...

Oct1813 05:18 PM
kira506

7 
504 
I am sure this is a set of naieve question first of all. However i'd appreciate someone taking the time to enlighten...

Oct1813 04:38 PM
James MEng

10 
564 
Hi,
Energy is expressed in J or eV, but E= hf
As planck constant h is J.s is it possible to express the energy of...

Oct1813 09:04 AM
DaleSpam

68 
1,970 
Why do we use the coordinates of r in terms of x,y,z?Why dont we express coordinates of A in x,y,z?

Oct1813 07:50 AM
CompuChip

7 
450 
Hi,
what is the lowest visible frequency? can anyone see light with f less than 4*1014 Hz?

Oct1813 07:09 AM
Simon Bridge

7 
406 
Do magnetic field is produced in all the following 3 cases?
Case 1: An isolated electron moving linearly with...

Oct1813 06:44 AM
Crazymechanic

30 
3,023 
Hi,
I did read an article (Norwegian one) about heat pumps. Several owners claims that the annual costs for...

Oct1813 03:58 AM
CWatters

24 
773 
For those unaware, geometric algebra is a mathematical language that generalizes and simplifies a lot of the tools...

Oct1713 11:29 PM
primetimeblues

0 
574 
Hello everyone,
My issue is regard a conversion from lumens to ~photons or energy at varying wavelengths. I am...

Oct1713 11:07 PM
davenn

2 
476 
Hello All,
I work in the refrigeration industry, and I'm trying to put a hard number on a hypothetical situation....

Oct1713 09:31 PM
Chestermiller

1 
456 
In physic,is true that energy of an object is the same.So we undestand that Kinetic(max)=Dynamic(max).
Why is that...

Oct1713 04:43 PM
jfizzix

1 
435 
In the cathode ray production experiment, at about .01 mm of Hg, cathode rays travel from cathode and move towards...

Oct1713 02:40 PM
UltrafastPED

3 
673 
The visible spectrum of light from hydrogen displays four wavelengths, 410 nm, 434 nm, 486 nm, and 656 nm normally.
...

Oct1713 02:08 PM
UltrafastPED

1 
298 
Hi,
I have two questions related to angular velocity:
1. According to rotational damper, Torque = Viscous...

Oct1713 01:59 PM
D H

4 
539 
I understand the Fourier transform conceptually, but I am unable to reproduce it mathematically; I am very familiar...

Oct1713 12:40 PM
Radarithm

4 
435 
is the wavelength equal to the distance between the excited state shell and the rest state shell?

Oct1713 09:59 AM
keepit

3 
255 
Is momentum really conserved in a perfectly inelastic collision?
By definition there is no conservation of kinetic...

Oct1713 09:15 AM
nasu

27 
1,086 
Why the current entering and leaving the battery in an elctirc circuit needs to be same??plz provide a mathematical...

Oct1713 08:31 AM
sophiecentaur

4 
494 
please remove this thread

Oct1713 07:37 AM
materie

0 
339 
OK so I've always wanted to learn about how the mains power works in conjunction with things that you plug in ie....

Oct1713 06:03 AM
crissyb1988

24 
985 
Well, what do you think? And why do you think what you think?

Oct1713 03:28 AM
davenn

7 
1,198 
please note in the process proving bernoulli we use the CONTINUITY equation.Consider a situation wherein a pitot tube...

Oct1713 02:35 AM
boneh3ad

7 
391 
Equation of standing waves→ y=Asinkxcosωt
What do i get if i differentiate the above equation with respect to "x" ?...

Oct1713 02:17 AM
NihalSh

5 
403 
I have a project I'm tinkering with that involves a "gyroscope" that I want to rotate back and forth using a spring....

Oct1613 02:02 PM
AlephZero

1 
331 
Why the light emitted in spontaneous emission is poly chromatic whereas the light in stimulated emissions is...

Oct1613 07:30 AM
MikeGomez

2 
312 
Hi,
We're using a lockin amplifier to oscillate an AFMstyle cantilever (across a frequency sweep) and measure the...

Oct1613 06:48 AM
D H

1 
310 
Now although this is silly and quite crude (You have been warned), it is a legitimate physics question. I was sitting...

Oct1613 03:23 AM
Simon Bridge

3 
404 
Hi all, I recently read the wiki article on Plasma wakefield acceleration and it states that plasma is "The most...

Oct1513 05:12 PM
Superposed_Cat

5 
357 
http://www.lasertechn.com/index.php/toroidalmirrors
in the figure, what does S’s – for the sagittal plane means? the...

Oct1513 12:49 PM
Andy Resnick

4 
458 
Hi,
can I know what are the ways to show that the ground state particles of a Bose Gas possess 0 entropy?

Oct1513 11:47 AM
mfb

1 
312 
I learn that inertia means the tendency an object will remain from changes. Heavier object has higher inertia, which...

Oct1513 11:22 AM
Imabuleva

6 
504 
Hi,
In classical induction machine analysis, the induced voltage (or curl of the electric field) is equal to the...

Oct1513 11:16 AM
darkfeffy

2 
545 
EDIT: I don't see this as a coursework question, even though I use a textbook example to set up my question. I feel...

Oct1513 10:16 AM
atyy

6 
799 
I already know that the right hand rule could just as well be the left hand for the rotational motion vectors like...

Oct1513 09:39 AM
Imabuleva

10 
664 
Just need someone to tell me if I'm doing this right.
If I have accelerated a particle in which the mean free path...

Oct1513 08:46 AM
dauto

1 
382 
Can somebody explain to me what is the difference between double slit diffraction and double slit interference?, to me...

Oct1513 08:45 AM
jtbell

2 
388 
Dear PH,
Recently I have been trying to determine if a surface is iridescence or not. The most quantitative method...

Oct1513 08:42 AM
Samuelsart

9 
477 
Sorry for the wording of the topic I couldn't figure out how to make it fit.
If I passed a hypothetical square...

Oct1413 11:22 PM
meBigGuy

5 
489 