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

Apr2211 05:26 AM
ZapperZ

1 
45,480 
Say I launch an object (a cart) up a frictionless inclined plane at an angle of 'theta' to the horizontal.
...

Sep1211 01:25 AM
Ken G

3 
4,671 
Many runners twist in their upper body while they run. You can see this by watching the logo on their teeshirt move...

Sep1111 09:25 PM
Ken G

1 
1,326 
Hi,
If I have a magnetic field orientated in the xdirection, a dipole positioned on the zaxis how do I find which...

Sep1111 08:42 PM
Spinnor

1 
1,304 
So every mountain biker or motocross rider knows to never grab the front brake in the air. When you do the front end...

Sep1111 06:24 PM
berkeman

11 
1,754 
What are some currently unresolved problem in thermodynamics? Thanks

Sep1111 05:06 PM
Andy Resnick

3 
2,358 
Hi all. I was working on a circuit question with inductors and I then had a question. Lets say we have a simple...

Sep1111 01:30 PM
perplexabot

3 
1,263 
From Drude model. plasma frequency of gold can be calculated using following
parameters
Nau 5.90 1022 := × me 9.1095...

Sep1111 01:09 PM
anilbeer

0 
2,255 
Hey i need derivation of projectile motion..
All four equation..
including range,height,Xaxis distance,yaxis...

Sep1111 08:35 AM
BruceW

3 
3,568 
I read in this weeks Time (or maybe it was Newsweek) a statement that I have heard numerous times over the years and...

Sep1111 08:11 AM
Drakkith

21 
3,518 
1. My questions is: Can "expi/r with r=sqrt(x**2+y**2+z**2), the frequency w is given, monochromatic wave" be...

Sep1111 07:15 AM
DaleSpam

32 
4,778 
I am researching for a scifi screenplay that I am writing for fun. To keep bone density from losing the estimated...

Sep1111 06:04 AM
Yachtsman

10 
2,451 
Hello everyone. There is a little project I could use some help with.
I would like this done in a spreadsheet, so...

Sep1011 10:44 PM
mahela007

3 
2,579 
From: http://answers.yahoo.com/question/index?qid=20090223155307AAgqbWk
Question: Why are electromagnetic waves...

Sep1011 08:20 PM
skeptic2

4 
8,037 
Suppose we have an antenna which has large directional gain. Suppose the antenna broadcasts linearly polarized...

Sep1011 02:32 PM
Spinnor

2 
1,048 
Hello everybody,
I have some questions:
I'm talking only about travelling waves, not standing waves.
If a linear...

Sep1011 12:43 PM
Ken G

3 
1,666 
Spherical nonoscillating bubbles in a saturated liquid always tend to dissove, why?
If the pressure is already...

Sep1011 10:00 AM
Ronald_Ku

7 
1,305 
Hi, if you have the book: Physics for Scientists and Engineers 8E, Serway Jewett
On page 675 (Chapter 23), Example...

Sep1011 08:48 AM
sweet springs

2 
1,131 
for 1 mole of gas, the adiabatic factor gamma is given by Cp,m / Cv,m
where the C are molar heat capacities
so if...

Sep1011 03:59 AM
quietrain

2 
1,341 
Hi
I have physical mechanisms which can be used to sort particles in specific groups:
1. Particles with...

Sep911 11:44 PM
kakarot1905

0 
715 
why do we stand up while moving up a hill in bicycle?

Sep911 06:58 PM
Drakkith

2 
949 
This question relates to second harmonic generation from a sub 100 nm nonlinear film.
When light impinges on an...

Sep911 12:48 PM
johng23

1 
808 
Imagine that we have a charged parallel plate capacitor.
I hold a charge somewhere between the plates.
Is the...

Sep911 11:28 AM
chrisbaird

1 
797 
why cant a wave transmit angular momentum?

Sep911 11:12 AM
chrisbaird

1 
585 
Looking for a rough distance scale over which statistical methods begin to work, and macroscopic thermodynamic...

Sep911 04:36 AM
xts

1 
1,057 
Hello,
I'm prepping for a course I'm about to take and on the precourse syllabus it said I should be able to:
...

Sep911 02:51 AM
vanhees71

1 
965 
Hello,
I am currently trying to really come to grips with electromagnetic induction and Faraday's law.
The text...

Sep911 02:46 AM
vanhees71

3 
1,506 
I'm an astronomy teacher on a very tight budget. Before I really get into the meat of astronomical information, I...

Sep811 06:10 PM
Andy Resnick

8 
3,545 
An object undergoing simple harmonic motion will always have varying acceleration. That means for each unit of time...

Sep811 01:41 PM
raja.ganguly

3 
8,991 
If a magnetised neodymium ball has a definite north and south point, could you slice the ball in two, and weld 2...

Sep811 12:02 PM
r3born

8 
1,745 
A plane wave can be described by the real part of the exponential wave equation:
\mathbf{E}=E_{0}e^{i(kzwt)}
...

Sep811 08:12 AM
DrDu

1 
936 
Hello All,
I am trying to create an experiment to determine the center of mass and inertia tensor of an aribtrary...

Sep811 08:06 AM
Andy Resnick

5 
1,770 
Why doesnt helicopter turn in opposite direction of rotation of propeller?

Sep811 04:43 AM
A.T.

6 
1,566 
Hello. I'm trying to understand electromagnetic radiation. Any help would be appreciated.
From my understanding a...

Sep711 07:51 PM
Bob S

6 
4,697 
At the current rate of oil consumption, the world will run out of it in twenty years. The Netherlands is investing...

Sep711 05:09 PM
mheslep

15 
2,072 
I'm trying to derive the resonance frequencies for a simple fixedfixed beam, as opposed to a simplysupported beam.
...

Sep711 03:23 PM
Bill_K

2 
2,687 
if a bird sitting in a closed cage starts to fly what happens to its weight of the system
What in open cage

Sep711 01:56 PM
Simfish

6 
2,126 
There are several references to “lost” kinetic energy when trying to analyze motion based on the Conservation of...

Sep711 12:46 PM
Ken G

63 
6,726 
Okay I think I get this but I just want to make sure:
In a frictionless, fully insulated pistoncylinder...

Sep711 12:19 PM
timsea81

13 
5,450 
Hello guys,
I've been trying to solve Maxwell's Equations in a laser cavity, with length L.
However I cannot......

Sep711 11:52 AM
chrisbaird

1 
1,101 
suppose the angular momentum of the earth is omega (w) and a geo stationary satellite also moves with the same angular...

Sep711 11:49 AM
chrisbaird

2 
755 