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

Apr2211 05:26 AM
ZapperZ

1 
46,878 
Wikipedia suggests it is possible for some gases to exert negative pressure?
'Most often, gases and liquids are not...

Sep1610 10:20 PM
Andy Resnick

30 
10,300 
Hey everyone,
I'm a bit confused with the meanings of f, g, and fg subscripts in the thermo steam tables (e.g. hf,...

Apr1711 01:25 PM
AriAstronomer

2 
10,272 
Hello,
For a reversible heat engine between temperatures T_1 and T_2, the ratio of heat going in and out the engine...

Sep2310 06:48 AM
DrDu

116 
10,271 
This is a simple enough question, but no one has been able to give me a satisfying explanation. Most people compare...

Oct1212 05:51 AM
CWatters

25 
10,270 
Are there any applications for the lissajous figures? I haven't seen any applications for them besides the ABC logo so...

Sep2107 11:17 PM
Gokul43201

4 
10,267 
Hi all,
Will like to check if my below thoughts are right:
1) For a totally reversible process, it has to be...

Feb2610 02:05 AM
noobie_doobie

2 
10,255 
Hey all...
I'm trying to write a technical report and one part involves calculating the rate of flow of water...

Mar107 09:58 PM
preet

2 
10,241 
I've looked this up extensively on the web but nothing seems to answer this question satisfactorily. For example,...

Apr2207 07:44 AM
lpfr

10 
10,238 
Okay, and odd title, but let me continue.
I recently read a 15+ page argument on another board about what would...

Feb2610 05:51 AM
Lsos

23 
10,227 
Hello.
I know that entropy equals the Boltzmann's constant times the natural log of the multiplicity but I do not...

May1909 02:30 AM
vipul_rop88

4 
10,218 
Why is the SI unit for acceleration \frac{m}{s^2}(meters per second squared) when it is actually \frac{m}{\frac{s}{s}}...

May1508 08:30 PM
ffleming7

3 
10,217 
I have been trying to find the explaination why the wavelength of a wave is the limit of the resolution of an image...

Dec1307 05:42 PM
Claude Bile

1 
10,211 
work done in an reversible process is easy to find we have the function of P internal bt when it comes to irreversible...

Nov108 06:52 PM
Count Iblis

3 
10,207 
Hi all,
I was asked today by a friend a simple question but couldn't answer so I'm asking you.
Let's assume we...

Jul1509 06:04 AM
leviadam

4 
10,203 
This question came some time back in Stony Brooks exam. I have the solution also. But i am having some conceptual...

Mar3108 03:02 PM
zarbanx

2 
10,199 
F=ma
How do we define m and F? If their definition both come from this equation, then the equation doesn't really...

Oct1909 12:29 AM
Martin

31 
10,180 
pi = 3.14159...
angular frequency = 2(pi)f
theta = 2(pi)f t
t = theta / 2(pi)f
For theta = 0, t = 0
For...

Oct2004 07:47 PM
Pyrrhus

7 
10,168 
Hi,
I've seen a very very small drop of mercury in a little corner of a laboratory table and it likely dates from a...

Mar2809 03:15 PM
lalbatros

5 
10,159 
In grade school I remember the physics experiment of the cup of water turned upside down on a card, and kept the water...

Aug2905 05:06 PM
lightgrav

9 
10,157 
In the movie Speed a speeding bus is shown jumping a long gap in the elevated freeway. The Mythbusters test the...

Dec1709 11:32 PM
diazona

56 
10,146 
I always hear a difference between transverse and longitudinal waves, and, standing and traveling waves, but for me,...

Apr1112 07:50 AM
Doc Al

6 
10,142 
A 5 kg block and block X are attached to a rope which passes over a pulley. A 30 N force is applied horizontally to...

Oct1903 11:49 PM
sirfederation

1 
10,139 
Why a cellphone rings inside microwave oven? Does the microwave oven don't block cellphone radiation?

Apr3008 12:01 PM
mgb_phys

2 
10,138 
Hi,
Does anyone know an equation/approximation/model or other to estimate the capacitance between two coplanar...

Jun2210 05:53 PM
marcusl

7 
10,113 
Everyone here should be familiar with the office toy known as Newton's Cradle where a ball collides with a group of...

Jan1310 10:11 PM
Prologue

8 
10,110 
A ball being thrown, ignoring drag or wind, has an initial height, initial velocity, and experiences the acceleration...

Jan1312 09:42 AM
nelleyao

19 
10,093 
On an automotive forum, a member made a statement that compressed air won't hold as much moisture as ambient pressure...

Feb604 11:31 PM
desertwinds

4 
10,083 
Hi,
Was doing some testing for work, but a lot of my physics are gone! Hope someone can help...
Here goes:
A...

Sep2309 12:46 AM
rustyphysics

12 
10,081 
I understand that using F = qv x B and the fact that positive currents generate counter clockwise magnetic fields, it...

Dec1210 02:21 PM
compter

7 
10,071 
If a top is spinning in the horizontal x,y planes in a counterclockwise motion, the vector of its angular velocity...

Jan504 08:00 AM
Njorl

6 
10,043 
Hi, I didn't post this question in the Homework section as it is not home work and does not seem to fit with the...

Feb2009 10:04 PM
mcvwi623

5 
10,022 
If water and vegetable oil are added to a bowl, they do not mix.
If gasoline and vegetable oil are added in another...

Dec2706 08:39 PM
Gokul43201

32 
10,019 
Is the kinetic energy of a (not necessarily homogeneous) rigid body in translational motion and rotating about its CM...

Nov1206 01:00 AM
jtbell

10 
10,008 
Recently I was going through the derivation of wave equation
I want to discuss it to get my concepts fully clear by...

Dec110 02:58 PM
emailanmol

10 
9,975 
Energy can be neither created nor destroyed.
What is energy?. ability to do work.
what is work ? work = force x...

Jul1107 08:45 AM
Doc Al

88 
9,964 
I am new here and have always loved the history of science as much as the science itself. I have been intrigued by...

May610 09:11 AM
James A. Putnam

113 
9,964 
Hello.
I'm having troubles solving the enthalpy for an ideal gas.
From the equation H=U+PV, i could find H...

May1510 08:41 AM
quantoshake11

2 
9,949 
I'm a little confused about the analysis of TM and TE modes.
As per definition, TE modes have only H (magnetic...

Apr2312 08:53 PM
Bob S

15 
9,945 
In space if a space craft in the absence of a gravitational field stopped using whatever propulsion system it was...

Jun1910 11:51 AM
DaveC426913

10 
9,938 
What are you able to derive or integrate from a voltage vs. time graph? Like if I have a battery and a resistor and...

Oct2109 03:15 AM
mikelepore

4 
9,925 