General Q&A about physics of any type and at any level
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A computer can store some number $n$ of bits in memory, and it can perform some number $m$ of essential computational operations, such as addition or multiplication, and rewrite those bits to memor...
Presuppose that I need vinegar of $c$ concentration, where $c$ < any concentration listed below. Let $w$ be the price of water that I'll use to dilute. How do I deduce which concentration (of V...
Suppose we have a gravitational wave which obeys the equation: $[G_{tt}-c^{2}G_{xx}]h_{\mu\nu}=0$ Lets take the case where $h_{\mu\nu}\ne0$ so we are left with the classical wave equation.Suppose...
There are a couple different types of indoor air humidifiers. Most notably, the naive steam humidifier with a heating element, and then ultrasonic humidifiers. Now, heating water to create steam o...
We commonly say that something has a weight, which is synonymous with a mass. Things have a weight because the force of gravity is relative to something’s mass. Subatomically, what is mass? There ...
In the context of quantum field theory, why is it impossible for two photons (or other massless bosons like gluons) to collide and produce a single photon? This kind of a process is supposed to be ...
Gravitational waves can be derived from the non-linear Einstein field equations and since they are by definition waves they must obey the wave equation: $u_{tt}=c^{2}u_{xx}$ but in General Rela...
Question I was wondering what force make drop slow down? Does every time a drop push toothpick back into bottle? And of course how to solve it. Struct This is a bottle be pierced by a wooden too...
Starting from the classical osmosis experiment, a U-shaped tube with a semi-permeable membrane, I would like to consider the case when the solute added to one of the compartments (labelled A) is co...
At home daily, I need to mix my table salt + COLD tap water. As "Marine salts dissolve faster and more thoroughly when added to circulating water," I "use a powerhead to speed up mixing time — my V...
Say we have a four underwater components tidal power / hydro power system. Component A. A propeller would always orient along the same direction regardless the direction of the flow. This is th...
Part 1 Say we have a round water pool, the radius is 10m, and the water depth is 2m. C is a fixed point: Fixed on the surface of water. Fixed at the center of the pool. F1 is stable forc...
I'm trying to understand the uncertainty principle and its implications for particle measurement. From what I've read, it seems that the principle states that we cannot simultaneously know the exac...
Suppose we have a arc of charges with some charge density $\lambda(\theta) = sin\theta$.I am using polar coordinates for convenience.But how can I find the direction of the unit vector of the net e...
I need to separate these two parts, the opposite of the GIF below. While my hunky husband was lifting the chair up, and my brawny brother pushing the frame down, I kept hitting the top of the slid...
The general formula for a EM wave (solving for the E field) is: where $\varepsilon = \varepsilon _{r}+j\frac{\sigma }{\omega }$ My professor told me that the conductivity of vacuum is 0 so we...
Suppose we perform the double slit experiment , but we fire instead 2 electrons instead of 1. In the double slit experiment performed in the 1920s a interference pattern was observed at the screen...
Lets say we have a mass connected to a spring.Assuming not any friction the ODE which describes the system is $m\frac{d^{2}x}{dt^{2}} = -kx$ We can set 2 Dirichlet boundary conditions $x(0)=0$ an...
I never grokked the optics behind LightHouses and the WW2 poster below work. LightHouse beams are narrow and focussed. Doubtless, the light source can fail to illumine a seafarer or the enemy subm...
If we have a LC high pass filter the transfer function H(s) becomes: $$ H(s) = \cfrac{sL}{sL + \cfrac{1}{sC}} $$ If we solve for s to find a pole of the transfer function we get: $$ s = j \cfrac...
Maxwell's first law in differential form states that $$ \triangledown \cdot E = \frac{\rho}{\epsilon_{o}} $$ . In case of 1d can we say that $$\rho = \lambda$$ where $$\lambda$$ is the linear char...
May it be that there are more than 8/9 planets in our solar system which aren't detectable with the current technologies? Is there any theory suggesting that our solar system has more planets, all...
Please see below screenshot of 15:59.The LED spot light (fastened to the front of the boat) illumines merely a few meters in front, and fails to illumine most of the water between the boat and the...
I'm interested in knowing the surface temperature of both sides of a double-pane or triple-pane window. Given the R-value of the window, and the air temps outside and inside, how can I calculate t...
I want to write some code to control my whole house humidifier. I want my code to calculate the percentile relative humidity above which dew will form on my windows. I have sensors for air tempera...
These WorldFamous companies advertise that their lenses can control myopia for kids, NOT adults. But none of these lenses are approved by FDA. I asked my optometrist why merely kids, not adults. Bu...
In classical physics book of kleppner, i read that An atom can "jump" from one stationary state a to a lower b by emitting radiation with $E_a-E_b$. The frequency of the emitted "package of radi...
Suppose we have a free falling object inside a planet's gravitational field with strength g.The planet's atmosphere provides a drag force which is dependant from the u^2 of the particle. Suppose t...
Im designing a capacitor and I have decided to make the surface of 1 plate of the capacitor bigger than the other plate. How are the charges sorted through A2?Are they spread out to cover all th...
With time dilation a cosmonaut could travel forth in time, especially in light speed. But are there much lesser speeds which might be achievable by humans in the next 100 years which could also in...
Suppose a ferromagnetic material with initial magnetization $M_o$.Is there some specific formula which calculates the total magnetization $M$ as a function of $M_{o}$ and the Curie temperature $T_{...
Suppose we are using a force gauge to measure gravity in a planet. We set the gauge force to the 1N range which has a resolution of .01 N. From its specs the error introduced during the measurmen...
Two weeks ago, my carry on worked perfectly. But last week the detachable wheels stopped rotating smoothly, when I tried to glide my carry on. The wheels budge JUST A TAD when you push them hard, b...
Get 2 conductors and seperate them we can use Gauss's law to calculate the capacitance created by the seperation of the 2 conductors.Can we use other laws of electromagnetism to calculate the induc...
I was introduced to a somewhat novel derivation of the ideal gas law that starts by thinking about the number of microstates of an ideal gas, $\Omega$. Say we have a gas with a single particle in a...
When a pendulum made of a conducting material moves through a magnetic field, it's a well-established fact that it experiences a retarding force, thus slowing it down, however, I'm unable to unders...
We know that electrons always repel electrons. But, if somehow they collide, then what will happen? I found a related question of above one in Quora. An incoming electron can instead make them ...
$$F=F(q,p,t)$$ $$\frac{dF}{dt}=\frac{\partial F}{\partial q}\frac{\partial q}{\partial t}+\frac{\partial F}{\partial p}\frac{\partial p}{\partial t}+\frac{\partial F}{\partial t}$$ $$=\frac{\part...
If I have a rocket with some known number of engines $n$, each producing thrust with arbitrary direction $T_n$ and center of thrust $r_n$, the total thrust amount and direction $T_{total}$ is equal...
In the lab I changed the angle the light hits a photoresistor and it doesnt obey Lambert's cosine law the conductivity of the photoresistor drops fast from +-20 to +-30 degrees angle.Why?
Suppose we have an electric dipole of charge Q+ and Q-.The charges of the dipole are fixed (they cant move closer to each other than they already are).If we place a test particle at some distance r...
My optometrist said that round eyeglass lenses are OPTICALLY better than rectangular, particularly to correct myopia. He was NOT referring to fashion or style. I couldn't understand his explanatio...
The title is a framing for a theoretical question; I'm not asking for practical advice. A friend was recently in this situation and my attempts to apply what I remember of a couple semesters of co...
What examples of a system can be described by a system of ordinary differential equations?
Should Earth's moon colonies being deep underground ensure natural heating? By natural I mean "non artificial" i.e. not from "artificial" air conditioning. The question is based on the thought th...
I was wondering what's the physical meaning of Laplace operator. $\vec\nabla$ actually represent a field. I had seen that Laplace operator is written as $\vec \nabla \cdot \vec\nabla=\nabla^2=\Delt...
Would a colony on earth's moon need to be deeply underground to ensure more natural gravity (by getting closer to its core)?
What are the SI units of the wavefunction Ψ(x).I know that [Ψ(x)]^2 describes the probabilty of finding a quantum object at a certain quantum state but what about the wavefunction instead?
Which one is correct? $$E=mc^2$$ or $$E^2=(mc^2)^2+(pc)^2$$ I mostly seen $$E=mc^2$$ from my childhood, and when I was learning problem solving in relativistic mechanics I had seen $$E^2=(mc^2)^2...
IKEA discontinued this NOVEMBER lamp in 2007, but I still use it. IKEA confirmed that they did not intend or design any cover or share with this lamp, and the light bulb is supposed to be exposed. ...
