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

Apr2211 05:26 AM
ZapperZ

1 
47,680 
Hi, my question is about determining the damping ratio for the upper springdamper part of the system given in the...

Dec109 12:11 PM
SystemTheory

1 
2,771 
I have a transfer function for system.
23.23*s + 1.421
 = tf
s^2 + 25.88*s +...

Jul1010 10:02 AM
stevenb

2 
2,844 
Typically photon attenuation is determined by the equation I = I_0 \cdot e^{  (\mu \cdot z)}. The variable mu is...

Sep805 03:57 PM
ehild

5 
1,091 
I've got data that's force (g) against time for an SDOF system (with a bit of noise). The main thing I'm interested in...

Nov811 07:14 AM
AlephZero

1 
1,282 
Hello All,
I have some basic damping related questions that I am hoping you all can shed some light on or suggest...

Nov612 03:44 AM
K^2

5 
897 
Unfortunately, magnetic fields are by their nature invisible, but scientists from NASA’s Space Sciences Laboratory...

Jun308 11:37 PM
SF

2 
1,556 
Today I was outside to get some grass for my rabbit. I took some yellow dandelions too, but as I entered the elevator...

Apr1308 06:39 AM
Tachyonie

3 
1,577 
hi,
recently i notice that there is a dark border around all the streetlight at night. what is this phenomenon...

Feb1114 05:55 AM
Simon Bridge

2 
204 
I am doing a lab for my optics class. My group has chosen to set up a simple dark field imaging device using a HeNe...

Mar1109 07:47 AM
Andy Resnick

1 
827 
I was working on some dark field filters and I was wondering if you could substitute the black spot in the centre of a...

Apr709 06:28 PM
Andy Resnick

3 
936 
Hi, I've been doing Fraunhofer diffraction and I have been getting dark spots in the middle if my patterns, not...

May611 08:37 PM
Redbelly98

3 
819 
Hi Everyone,
I am trying to calculate the exit velocity of a dart which is propelled by compressed air. Please see...

May2312 06:38 AM
haruspex

1 
931 
does dB increases when voltage increases?can sum1 state or declare a formula or proof?

Feb2510 12:53 PM
Bob S

1 
1,997 
DC doesn't cause electromagnetism? That is what our teacher says. Can anyone explain why it doesn't? As far I remember...

Nov1109 02:59 PM
Dadface

11 
1,341 
To increase a DC generator's turning effect, we increase the number of turns of the coil. How does this increase the...

Sep2912 04:51 PM
Philip Wood

1 
1,331 
Hi, I have a question related to the DC motor that i hope you geniuses can help me with.
By Fleming's Left hand...

Sep2312 12:58 PM
sgstudent

6 
874 
Another intersting point on home electronics raised was  why does every device you purchase have it's own...

May1305 03:40 PM
zoobyshoe

39 
3,412 
hello ,
DC (I guess AC too) power supplies have 3 terminals: plus, ground, minus.
If I set the voltage to 30...

Sep2808 12:03 AM
Phrak

3 
9,053 
Hello, can someone please help me out here, i want to step up the voltage of a 1.5V battery to 300V, i know that to do...

Dec1207 03:53 PM
alvaros

1 
1,785 
de broglie wavelenth of a perticle approaches zero faster than 1/v as its speed approaches the speed of light..how can...

Oct809 02:02 PM
hasanhabibul

0 
594 
In order to understand about DeBroglie's explanation on Bohr's second postulate,concept of standing waves should be...

Apr1813 07:23 AM
Philip Wood

2 
1,029 
My textbook says that dETdS+PdV<0 for all irreversible processes. However, for reversible processes, the author says...

Jul1212 10:54 AM
Studiot

21 
1,278 
Are elemental particles subject to entropy? Are there dead electrons "no spin".

Dec711 03:18 PM
mathman

6 
1,264 
The noslip boundary value constraint for NavierStokes solutions was explained in my fluid dynamics class as a...

Apr3012 09:33 AM
Andy Resnick

1 
1,039 
Hi,
I've been trying to figure out a formula which describes the relation between the area, load and negative psig...

Jul2007 12:29 PM
deimors

2 
1,444 
Firstly, I'd like to announce that this is not a homework question, it is an example of a problem I thought up to...

Apr1009 04:24 PM
arildno

3 
2,039 
My question is what causes death wobble? Let me explain more...
The vehicle I've experienced this on is a Jeep with...

Aug2209 04:03 AM
rcgldr

19 
16,010 
Helloooo. I'm debating a creationist and he consistently is bringing up the laws of thermodynamics to try and 'prove'...

Jan406 08:03 AM
Doc Al

17 
2,944 
Just a question:
I do know it is possible to have a debye layer in a electrolyte. But is it posible to have a Debye...

Jul1506 12:24 AM
Clausius2

2 
4,880 
Hello, I am new here.
I was reading Wangsness electromagnetic fields and he delves into a short discussion about...

Aug1514 07:14 PM
Greg Bernhardt

1 
251 
Hello,
Here's my challenge: I want a physics model for how one would go about in order to decay the moon's orbit....

Dec213 09:45 AM
BruceW

10 
1,176 
Ok, so I was doing this problem, *NOT* a homework problem, where I was solving for the force (and eventually, the...

Jun1310 06:05 PM
russ_watters

2 
2,579 
Hi there, sorry for asking a question as my first post instead of contributing to the community however I have a...

Jun813 04:21 PM
Aero_UoP

4 
1,409 
I posted a question as thus :
A train moving at 100 km/hr uniformly decelerates at a rate of 10 km/hr each hr. How...

May507 09:13 AM
ZapperZ

7 
1,640 
A basis for any 3dimensional vector space must have 3 vectors in it.
So the acceleration of any object in ℝ^{3}...

May213 02:54 PM
AlephZero

6 
752 
This is a short conceptual question.
If I place a heat sink in a sealed container, and than raise the ambient...

Sep610 06:18 PM
Dr Lotso'watts

4 
660 
Greetings everyone:
I am trying to create a software for estimating temperature for a liquid in a group of tanks...

Apr811 03:54 AM
sandeepbwes

0 
494 
In thermodynamics heat reservoir has a lot deegres of freedom. Can you tell me some examples of that deegres. Thx

Mar1912 11:35 PM
Andrew Mason

3 
770 
I was fascinated by the Wired article describing such an elegant engineering solution for remote data collection deep...

Feb2807 10:48 AM
russ_watters

4 
1,530 
See here:
http://www.physicsforums.com/showthread.php?t=299561
And:
...

Mar1409 06:18 PM
rcgldr

4 
1,074 