I can't find the answer anywhere here's my question. can a centrifuge exist outside a field of gravity. More specifically, in a theoretical void of nothing without stars in view or any point of reference for comparison how could motion like spinning or acceleration exist?
How to derive (proof) the following
trace(A*Diag(B*B^T)*A^T) = norm(W,2),
where W = vec(sqrt(diag(A^T*A))*B)
&
sqrt(diag(A^T*A)) is the square root of diag(A^T*A),
B & A are matrix.
Please see the equation 70 and 71 on page 2068 of the supporting matrial.
I've heard quite frequently that events inside the event horizon of a black hole are causally disconnected from the rest of the universe.
I take it to mean that while outside events can interact with the events inside of the horizon, the reverse is not true i.e. inside events cannot interact...
Suppose one forgot to protect outside water spigots against below freezing winter air. If there is a stiff wind, will, as I think, the spigot freeze sooner than if the air is calm at the same temperature?
Also, wouldn't the case of calm air actually be more complicated to model because the...
Summary: Does the image distance q in the lens-maker's equation mean where real images form or where any image at all forms? If the former, what separates the real image from all other reflections?
Hi all,
I attached a series of images taken with a camera for a concave mirror, the Pasco...
I've built an insulated chamber to protect a sensitive instrument at freeze temperatures in the winter. The instrument is mounted on a telescope, so the heat inside the chamber will slowly dissipate in the ambient. A digital PID thermostat is used to keep the temperature at a safeguard level...
If we put a positive charge outside of a conductor, there is an induced charge, but if we put a positive and negative charge inside a conductor, there is no induced charge?
I would like a program to read in a file entered by the user via the command line, which is then used in the main body of the code.
See example code below:
#include <iostream>
#include <fstream>
struct run_t {
std::string file;
};
run_t run;
const POINTER* ptr = toy(run.file,0);
int...
If outer space is a vacuum there is no force in a vacuum to create friction, therefore if a vehicle i.e. spacecraft space shuttle is it a vacuum and produces any amount of thrust it should move a constant through space continuing to add thrust will only make the craft move faster until it...
I know that inside region 1, the D-field is zero as it is a conducting sphere, the E-field must be zero. It makes sense that in region 2 (inside the dielectric) there is a D-field.
My question is, is there a D-field outside the dielectric material (r>R)? Obviously there will be an E-field, but...
If it's 20degrees outside and 68degrees inside it's warm when you come in from the cold. If it's 100degrees outside and 68bdegrees inside if feels cool. 68degrees is constant. Why does it feel different depending on the temp outside?
Potential inside is given as in ,https://en.wikipedia.org/wiki/Method_of_image_charges, which is the sum of excitation and induced potential. When the charge is outside it is easy to argue potential is zero in the sphere. But when we have charge inside and image outside, what is potential...
I think I want to pursue physics, but I can't seem to keep up with the pace of a university class. I also don't like the format. How would you go about doing this?
Coulomb's law for three dimensional space is an empirical law that describes the forces between two stationary point charges and is defined as:
\vec{F}=\frac{K q_1 q_2 (\vec{r}_1-\vec{r}_2)}{|\vec{r}_1-\vec{r}_2|^3}
From Coulomb's law, the magnitude and direction of an electric field produced by...
Say we just created a particle (high probability of one-particle state), is the probability of a very far away detector getting triggered at the time of creation (probability of finding a particle outside of its light cone) zero according to QFT?
Since we can detect particles and make...
So here was my first go around at it:
At first it made sense in my head but don't think my process is correct. Then i noticed the example in the book:
I guess the reasoning isn't 100% there in my head and if i don't have an actual σ, how will i cancel out any legendre polynomials due to...
I have solved the first 2 parts.
For the 3rd part, I have obtained the equation:
T(x) - T0 = (T1 - T0)e^(-Φx/fc), where f = fm in the question.
How do I obtain that expression for H?
Thank you!
I know that for the infalling observer the horizon is a fake singularity that can be removed via the Eddington-Finkelstein co-ordinates but wouldn't the classic Swartsheild co-ordinates still apply for the outside observer?
So, while for the infaller it takes a finite time, the outside...
Given the state of affairs with COVID and its effects through closures of "unnecessary" services and colleges working more online for the time being, does anyone have advice on how to go about gaining physics research experience outside of the university?
At this point, I'm about 18 months...
Griffith's says this, and I'm not exactly sure why...
If you had a solid, spherical, and externally induced conductor... Does this mean that IMMEDIATELY outside, when you're infinitesimally close to the surface, E looks like this? If you surround the entire conductor with a Gaussian surface...
How is this possible? I can't think of what could be absorbing Co2 inside my house, when I am producing it at a pretty high rate.
I have my HVAC running on a frequent cycle mode also. I have no plants.
The sensor...
Hey, I figured the general discussion would be the most appropriate place for this discussion.
I finished my PhD a couple years ago and moved to my original country. I still keep in touch with my previous adviser as we are still working on my thesis research, which is great. However, because of...
Today when I am reading Griffith's electrodymamics on surface charge and force on conductors, I have come across two very ambiguous terms: electric field at the surface and immediately outside the surface.
The context of these two words is as follows:
The electric field immediately outside is...
I have been reading Griffith's Introduction to Electodynamics and i am currently at the chapter about magnetostatics. There is an example about a long solenoid with n units per length and radius R that shows a way of finding the magnetic vector potential. The magnetic field inside the solenoid...
Summary:: What does this mean?
Discussion changed to meaning of words - moved from Biology
When a channel in a plasma membrane (or really anything else in everyday life) is "open to the outside" of the membrane (or wall), what does that mean? Does that mean if you're standing outside of it then...
Summary:: What percent of the universe is outside of galaxies?
Hello,
What percent of the universe is outside of galaxies?
I need this information for a writing piece I am doing. I need specifically to be able to state that if someone was to randomly relocate to somewhere else in the...
I'm wondering if the outside color has an influence on the thermal depletion of things such as a thermos, a wall, etc.
Assuming, obviously, there's no sunlight hitting on them.
It certainly has, but what difference percentage can we typically expect for example for bottles such as the ones on...
I was wondering if there is a way to deduce the solution of the potential of a charge outside a sphere given by the image method, though Green functions. Because of a Dirichlet condition (GD(R,r')=0), I know that a solution can be written as GD=Go+L, where ∇2L=0. But in order to approach this...
My attempt:
I realized after i had tried to solve the problem that the current must be constant in the cables. But no information about where the cables has radius a and b is given so how would I go about to find an expression for the current?
Thanks in advance!
I read before that room air conditioner is not supposed to suck in air or particulates/dusts from outside but my air quality monitor can detect some increase in pm2.5 particulates when the aircon is opened. Is it because its sucking those particulates from outside or the fan of the air...
Hello,
I hope this is the right place to post about this.
I live in a multi-unit condo, and I have a window that I am trying to lock and unlock from the outside. The window is from the kitchen and looks out onto a public-ish breezeway where I can access easily. I know this might seem a...
Does neutron decay outside of the nucleus occur faster, slower, or at the same speed when the environment it is in is near absolute zero? Do any external factors affect the speed of a neutron decaying?
In his book on electrodynamics, Griffith talks about the magnetic field outside a solenoid. Firstly instead of dealing with a typical solenoid with closely wound loops, he instead works with a cylinder with a surface current that has no z-component. To get the angular component of the B-field...
Not a homework. Just self-studying electromagnetism.
I am stuck at understanding the very beginning of the solution steps in this example:
The E as given in the solution is the field away from a long straight line with charge Lambda. That's clearly not the current configuration.
E should...
Hi! I need help with this problem. I tried to solve it by saying that it would be the same as the field of a the spherical shell alone plus the field of a point charge -q at A or B. For the field of the spherical shell I got ##E_1=\frac{q}{a\pi\epsilon_0 R^2}=\frac{\sigma}{\epsilon_0}## and for...
Plot for the ring ^
Calculations for the Square ^
Plot for square without cosg on the outside calc ^
Plot for square with cosg on the outside calc ^
As can be seen the formulas for the square conductor do not connect at R, which I'm not sure if they should or if they should not as in this...
Hello everyone,
There is an electrical field inside and outside (at the same time) the spherical hollow conductor when we place positive or negative charge inside, isn't it?
I know this is because of the induced charges on the inner and outer surfaces of the conductor. There is no field inside...
I'd like to know if anybody can tell me either;
How large a wheel would have to be for the outer edge to travel faster than the speed of light if powered by a motor that's around now.
We'll say the wheel is in outer space to eliminate drag and such
I bring a dielectric in a region with electric field ##\vec E_0##. Net electric field ## \vec E_{net} = \vec E_0 + \vec E_p ## , where ## \vec E_p ## is electric field due to polarization of dielectric.
For linear dielectric, ## \vec E_p ## is 0 outside the dielectric. So,
## \vec E_{net} =...
I thought I should use the ideal gas law to find out moles of air that would be transferred out through the window but the temperature and volume outside is not known. Can you help me further? thanks
Summary: hypothetical experiment, how would neutron core behave in such a circumstance such as, if we teleport 1mm^3 of neutron star core from it outside.
how would the 1mm^3 neutrons behave?
1. Would it be stable/no change
2. Would it decay into cosmic radiation
3. would it decay into...
Outside of QM, do perfectly linear waves really exist in nature? I am referring to just those waves that also have dispersion - in which the wave components have differing phase velocities.
... or are we just using the mathematics of linear systems to approximate nonlinear systems?
Thanks in...
I want to compute the fraction of time both particles spend outside the finite potential well. All I can get is the probability to find them outside. The wavefunction outside the potential is:
$$\frac{d^2\psi}{dr^2} = -L^2 \psi$$
Where:
$$L = \sqrt{\frac{2mE}{\hbar^2}}$$
Solving the...
If a charge is put inside a spherical shell, why is the electric field outside the shell independent of the location of the charge? Gauss's law could find that the net flux is independent, but not each individual field?
Is this something about the surface charge density being independent of...
Hello all. I have a question about gasses and pressure: Is there a way to calculate how strong a material making up a balloon has to be to withstand a given pressure difference between the inside and outside?
In other words, if I have a balloon I need to fill to a pressure of 10atm inside vs...
Homework Statement
This is not a homework problem, I'm working through griffiths Electrodynamics on my own.
Homework Equations
when there is an emf source, since electrosatic fields integrate to zero around a loop
The Attempt at a Solution
The solution claims that since the integral of f...