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

Apr2211 05:26 AM
ZapperZ

1 
46,997 
Hi
When talking about atoms absorbing a photon, a classical picture is utilized. The intuitive picture often...

Sep412 11:07 AM
Darwin123

7 
1,085 
Why did Newton define force as F=ma instead of stuff like F=m*(a^2) or F=(m^2)*a?

Sep412 01:03 AM
Rap

32 
4,478 
most(or all) proofs i have seen of gauss's law is based on coulumb's law. however coulumb's law is based off of...

Sep312 05:01 PM
bigerst

3 
850 
If we imagine a capacitor as two conductors held a distance d apart from each other, we can find easily that the total...

Sep312 03:09 PM
aaaa202

4 
726 
I was wondering what will happen to a hovercraft which is designed for a given air film thickness, is. slightly lifted...

Sep312 01:54 PM
hover guy

4 
715 
So, I'm trying to understand how tension works between a cable.
No, not homework. A book example. I have the answers....

Sep312 01:01 PM
Doc Al

9 
1,336 
Two 140kg satellites collide at an altitude where g=8.7m/s2
and the collision imparts an impulse of 1.8x105N.s to...

Sep312 10:54 AM
Doc Al

1 
1,228 
The D'Alembert's Principle states that:
\sum_s \cdot \underline{δr_s} = 0
s  labels particles
That is when ...

Sep312 09:48 AM
Studiot

3 
1,128 
In this document, how do I get 3.2 on page 12? I assume it is the EulerLagrange equation given in 3.1 just rewritten....

Sep312 08:41 AM
dextercioby

2 
814 
I had quite a few posts about this some weeks ago, but I am still not sure about it. My question is about why you can...

Sep312 06:46 AM
voko

7 
1,134 
Is it possible for a surface that reflects all visible light, and absorbs absolutely none to exist, Or would that...

Sep312 05:02 AM
Simon Bridge

11 
933 
Dear friends,
In small oscillation problem of classical mechanics, the generalized force is zero (Eq. (61)) of the...

Sep312 03:55 AM
saravanan13

0 
652 
The flux rule for motional emf can be stated as:
d\phi/dt = \epsilon
I have some questions regarding this. 1)...

Sep312 03:51 AM
harrylin

3 
906 
Consider a freely rotating body. Let the axis of rotation be the zaxis. For simplicity assume all the mass of the...

Sep212 02:57 PM
birulami

1 
1,524 
Says Wikipedia: "The moment of inertia is a measure of an object's resistance to any change in its state of rotation"....

Sep212 09:46 AM
Simon Bridge

3 
665 
This page
http://hyperphysics.phyastr.gsu.edu/hbase/electric/capeng2.html
talks about how the battery does...

Sep212 08:33 AM
DaleSpam

13 
1,281 
Forums like these give me faith in humanity.
I am busy with little project and I've just come out of angular...

Sep212 07:19 AM
The Sparrow

6 
932 
In the question I am not able to understand what the scenario is. Is it that we are removing the P force after...

Sep112 05:03 PM
haruspex

7 
1,053 
I have only recently found out about this idea (many thanks m.e.t.a.) and I am curious about it. Could it be used to...

Sep112 03:38 PM
Rooted

5 
1,837 
I'm a little confused about what exactly work/energy is. I understand that if I exert 10 N o a box over a distance of...

Sep112 12:31 PM
Naty1

3 
817 
Hi all,
I've been looking at some buoyancy problems and one continues to vex me, how to calculate the new fluid...

Sep112 02:06 AM
haruspex

1 
1,058 
Was not sure where to post this specifically, but I am looking to calculate the possible distance traveled by by a...

Aug3112 08:12 AM
mfb

6 
962 
I'm just confused...
I know that magnetic fields can do work only on pure magnetic dipoles like a bar magnet. Based...

Aug3112 07:17 AM
harrylin

407 
36,975 
Hello everyone.
I am fairly familiar with physics. However I have a question regarding the math behind a lever...

Aug3112 06:20 AM
cmmcnamara

4 
777 
Given the following instantaneous parameters and constants...
Known:
d = air density = 1.24
Cr = rolling...

Aug3012 11:07 PM
voko

6 
1,343 
If I am trying to minimize triboelectric charging. What two substances when rubbed together would produce minimal...

Aug3012 05:37 PM
DrZoidberg

2 
976 
I had a thermal conductance homework problem where heat flowed through gold, and then silver. Both materials were of...

Aug3012 04:31 PM
Emilyjoint

4 
656 
Consider the Hamiltonian of Kepler problem
H(\boldsymbol{r},\boldsymbol{p})=
\frac{\boldsymbol{p}^2}{2\mu}...

Aug3012 03:32 PM
Clausius

0 
437 
Consider a current loop with a switch and an AC source in space, there is a point charge(electron) inside this loop,...

Aug3012 02:14 PM
Qreeus

34 
3,608 
Assume we have an ideal gas of N particles inside a thermally isolated cylinder of volume V, and that the cylinder is...

Aug3012 01:46 PM
Jolb

6 
1,902 
Hi, Im getting started on analytical mechanics but need some help understanding some of the things that is said in my...

Aug3012 01:10 PM
voko

19 
1,188 
I need a review of solenoid equations, such as equations for bar solenoids, toroidal solenoids, and toroidal solenoids...

Aug3012 11:09 AM
Prince Rilian

2 
954 
hi ...
These days i am trying to make sense of the various processes of thermodynamics and so far i have tried the...

Aug3012 09:03 AM
Studiot

3 
844 
I have an image taken with a camera. I know the f/#, focal length, CCD characteristics, and an approximate distance to...

Aug3012 08:54 AM
Andy Resnick

10 
1,331 
Here is a simple example about my issue with this. 1g ball (ball A) moving west at 10m/s hits another 1g ball (ball...

Aug3012 07:49 AM
mickybob

6 
3,269 
Here is a quote from one of the MIT notes on magnetism :
"Note that F(magnetic force) is perpendicular to v and B ,...

Aug2912 05:57 PM
gabbagabbahey

9 
1,078 
I have a question. All things being equal as far as flow and pressure goes...where would the gas preferentially flow...

Aug2912 04:08 PM
Integral

14 
921 
Hey I just wanted to check with y'all, but I feel I'm fairly well acquainted with momentum and the rules surrounding...

Aug2912 02:53 PM
A.T.

1 
1,021 
Hi everyone I have a quick question regarding heat transfer. I have yet to study heat transfer yet but I have a basic...

Aug2912 01:56 PM
pa5tabear

1 
599 
I need to calculate the torque needed to move an object in horizontal direction. The object is subjected to a force P...

Aug2912 07:34 AM
mfb

1 
867 