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

Apr2211 05:26 AM
ZapperZ

1 
48,230 
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 
1,659 
Here's the problem: you've got two carts sliding along frictionless tracks at an equal speed, etc... as they move...

Dec1910 06:40 AM
Doc Al

15 
2,673 
say you have a very very long (or infinite) straight wire the carried a charge (glued to the wire) and the wire moves...

Aug612 03:28 PM
bigerst

4 
984 
im reading introduction to electrodynmics by griffiths, the math techniques used is sloppy to the point of...

Aug712 06:52 PM
bigerst

9 
1,133 
is it possible to construct a system with only finite number of point charges of arbitrary magnitude at finite...

Aug1812 10:15 AM
bigerst

2 
1,010 
what creates magnetic fields, magnetic poles or currents? are those theories equivalent mathematically? i read in...

Aug2712 08:28 PM
BruceW

1 
532 
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 
866 
i was reading about derivation of Euler's equations for rotational dynamics (john taylor, classical mechanics, chapter...

Nov1812 11:18 PM
bigerst

0 
930 
I'm just uncertain (haha), what IS newton's Second law exactly?
F=ma, or F=dp/dt, aren't these defining equations for...

Jan2413 06:21 AM
Jano L.

12 
1,721 
i am currently reading griffith's book on electrodynamics, though he does an excellent job with the theory (along with...

Jan2513 11:09 PM
bigerst

0 
395 
Hello
I'm having a little bit of trouble with socalled rest frames. I will distinguish two cases.
consider...

Mar3013 08:17 AM
mfb

1 
469 
I got stuck going over the derivation of fictitious forces in rotating frames.
see specifically ...

Apr113 10:57 AM
BruceW

1 
439 
D=Drag Coefficient
p=Density of air
A=Cross sectional area
v=velocity
a=acceleration
F= force
F air=(DpAv^2)/2...

Oct710 07:48 AM
tinytim

1 
1,574 
I have read that air pressure is about 100,000 pascalls
which = 100,000 newtons/m2
which is enough to accelarate a...

Sep1705 05:04 PM
Astronuc

5 
6,069 
I'm a little confused about "voltage". We learned that voltage is somewhat similar to electric field: a way to refer...

Nov1108 12:32 AM
jtbell

7 
1,859 
Good day,
I happened across an interesting interactive JAVA applet demonstrating the diffraction of light through a...

Apr1806 06:48 AM
BigMonkey

3 
1,847 
This is a concept that has always eluded me. I'm a Biologist who works in the Pharmaceutical Industry and I need to...

Aug2107 03:02 AM
Imagelist

15 
3,616 
hello everyone. Can anyone please help with following questions?
1. Can coefficient of friction (both static and...

Nov313 01:30 PM
clem

1 
444 
Hello all,
I officiate high school and college basketball. One of our rules concerning a dribble states...

Oct3007 02:09 PM
berkeman

3 
1,146 
These problems are really giving me fits, I would really appreciate some help.
A 12200 kg sailboat experiences an...

Sep2204 01:11 AM
Simonnava

5 
4,052 
Hello All....
I am just wondering about something.
The lift equation is,
L= \frac {C_L \rho A V^2} 2
...

Oct2407 04:31 AM
white flock

4 
12,477 
Hi, in class we were talking about lenses and how there is a certain focal length where all images 'far enough' away...

Mar1911 03:53 PM
Andy Resnick

1 
1,010 
Dear friends, and science lovers,
I am doing some statics problems with moment( crossproduct).And I've been...

Nov1613 01:51 PM
jhae2.718

1 
637 
Someones like teachers in my country says energy is vector and scalar .
Is that true ?
Anyone can prov that ?

Oct2312 08:02 AM
Studiot

7 
11,746 
Hello all .
Why mater victory to anti/matter after big bang ?
There is any relation to gravity ?

Nov2812 04:16 AM
Drakkith

2 
504 
Hello all .
I have two questions
Energy can create force ? for apply a force we need energy ?
Think about one...

Mar1213 09:40 PM
DaleSpam

20 
1,633 
Hi there,
I have noticed that when the wadding pool I work at is draining, a small whirlpool appears over the drain...

Jul1211 10:20 AM
chrisbaird

1 
1,406 
Hi all,
I am wandering if I can apply the KramersKronig (KK) relations to the complex wavenumber k(ω) = k'(ω) + i...

Feb1014 02:52 PM
maajdl

1 
302 
I need to calculate the the load F (in multiples of W) required to keep the link ABC in equilibrium under the action...

Sep2710 11:43 PM
bijesh_msg

0 
898 
From theory, we know that Boltzmann entropy for a given distribution, defined through a set of occupancy numbers {ni},...

Dec2112 09:08 AM
Rap

1 
831 
I was reading in my geology book (Earth: An Introduction To Physical Geography, 7th ed. by Tarbuck and Lutgens, 2002,...

Oct2110 03:48 PM
Studiot

9 
2,783 
I am looking for educational derivation( or any available and detailed) of the key principle of statistical...

Apr2308 01:28 AM
bilha nissenson

12 
2,507 
When a cue ball is driven into another ball, it is either not accelerating or decelerating at impact. It has momentum...

Aug911 12:14 AM
rcgldr

1 
1,180 
If I combine 2 laser beams of different wavelengths, would I get a beat frequency of the difference between the 2...

Oct1511 02:46 PM
xts

2 
1,224 
I went for a run and measured time and distance. I wanted to estimate how many calories I used.
Suppose a ran a...

Dec1307 07:17 AM
Shooting Star

1 
2,564 
Hi
I am new to this forum. I am an amateur blacksmith/machinist/all around tinkerer. I took a class with a...

May2814 07:33 AM
Nugatory

4 
247 
Okay, first a brief intro. I studied math/physics extensively as an undergrad...but that was over 10 years ago now. ...

Sep310 09:08 PM
Bill M

2 
940 
Hello,
I'm trying to figure out a method of calculating the work done by friction on an object sliding down a...

Feb1711 04:32 AM
tinytim

14 
4,021 
If the crest of one light wave meets the trough of another light wave of the same frequency and intensity they...

Feb1708 02:04 PM
Jakell

1 
3,952 
what exactly is the cutoff ratio, in physical terms?

Jan208 03:57 PM
brewnog

2 
4,014 