Why does Newton's Gravitation Law work for objects nearby?]]>

Hypothesis is a theory which can after testing be accepted or rejected. But a postulate is something that is assumed to be true without proof.

Among other...

Postulates and pseudoscientific hypotehsis difference?]]>

https://en.wikipedia.org/wiki/Multiverse]]>

My question: what can we do so...

How can we melt ice in a microwave efficiently?]]>

I think there's something wrong in my question, please point it to me or please answer it.]]>

I have two questions about the solutions to Maxwell’s wave equations:

1. I always hear that E and B must be in phase. Why is this, mathematically? And wouldn’t this also be a solution:

B

E

In which case E and B...

Maxwell’s Equations Wave Solutions]]>

Magnetic Levitation (electromagnets?) for an 11th grader]]>

Lately I have been studying the Poynting Flux and I am familiar with the classic examples of how it can be used to describe the power being dissipated by a resistor and the energy flowing into a capacitor, but I have never come across a similar analog for how the Poynting flux...

Magnetic field and Poynting Flux in an Inductor]]>

## \frac {df}{dt} = \frac {\partial f}{\partial t} + \vec {v} \cdot \vec {\nabla} f + \vec {a} \cdot \vec \nabla_{\vec{v}} f ##

Although I was told this should more...

General Boltzmann equation]]>

I know that the pressure change of air outside is decreasing(as we go up = less pressure)

And as the balloon is rising it's increasing its volume.

but what happens do the pressure change

What happens to the pressure change inside a rising balloon?]]>

Lower limit in pair production]]>

See this image View attachment 216035

Are the Sun's rays reaching us always **PARALLEL rays**?

I will be thankful for help!]]>

How long would it take for gas to leak out of a space box?]]>

If we can create a magnetic cusp, but oscillate...

Containing a plasma with a oscillating cusp?]]>

There is a basic problem I am having with fluid dynamics that has been really confusing me.

I have been told that as a result of conservation of energy and Pascal's principle, for an incompressible fluid P

However, pressure is not...

Pascal's Principle vs. Bernoulli's Principle]]>

Understanding Entropy and the 2nd Law of Thermodynamics

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Understanding Entropy and the 2nd Law of Thermodynamics - comments]]>

As Alpha particle is a high energetic particle when it interacts with electron of gold atom it ejects the electron. Is there any probability if...

Ruthorford's Gold foil]]>

View attachment 216481

Calculating the real and imaginary parts of the complex wave number as in equation (9.125) lead to equations...

Finding Real and Imaginary Parts of the complex wave number]]>

Copper and magnetism]]>

$$\frac{\partial^2\psi}{\partial t^2}=c^2 \nabla^2 \psi$$

which describes practically about pressure and propagation speed into space and time. I know also this equation...

About acoustics physics -- The Wave Equation and diminishing sound intensity]]>

The wire that connect the two components is a very small cylindrical conductor, so it should have a surface charge distribution. It's that correct ? If no, why ?]]>

Time in the present

Time in the past

We are living in the 'present'.

My question: how 'big' is this present time?

It might help if you think of a pen placed on a white sheet of paper. The pen represents our present time. The white space above...

How 'big' is the present moment in terms of time?]]>

My understanding is that when light (with some frequency and polarization) hits the interface between two media (each with some frequency-dependent material properties), the Fresnel equations apply. This tells us how much light reflects back versus refracts across the interface.

I'm...

Overview of General Fresnel Equations + Complex IORs]]>

I was thinking that using AC to supply power to a lamp would cause it to flicker, considering that the potential difference keeps changing signs.

This would mean that the current supplies voltage to the lamp, only to take it back after a really small amount of time. Voltage say's...

Wouldn't using AC to power a lamp result in flickering?]]>

Please, I learned that a wave is something the photons "surf" on, like, in one electromagnetic wave, can have many photons.

So, is this true? Like, I though that one gamma ray and an infrared photon would ride different waves...

More: the light from the...

The relation between photons and waves]]>

Why is it obvious that this Lagrangian is Lorentz invariant?]]>

Current Density between two infinite plates]]>

I've measured the radius of a sphere (a very regular one) with a micrometer of 0.01 mm resolution.

I took 3 measures (rotating it between each measure), and all of them were...

Error in the average of same-value measures]]>

Rocket Mass Ratio Query]]>

Assuming the racket string tension to be 50 lbs...

How to find velocity given force and time? (tennis)]]>

Thank you in advance.]]>

Gauss' Law Diatomic Hydrogen]]>

Lever, bar, and mechanics why does this happen?]]>

In Maxwell...

Objects get smaller as they become more distant]]>

I have been reading some of the literature recently concerning the Kardar-Parisi-Zhang equation and the words "universality" and "KPZ universality class" keep appearing. I already did a cursory wikipedia search on the subject, but it did not make much sense to me.

Can you please...

What is the formal definition of a Universality Class?]]>

I have a pair of eyeglasses with screwless spring hinges that uses spring steel metal strip (see full pictures below). I’d like to understand something about it. When the temples are fully opened.. the spring metal strip are in...

Spring Steel Metal Strip in Eyeglasses question]]>

An object moves outward in shaft radially due to centrifugal force.

lest say it weights 1kg . in a timestep=0.0001 it travels 0.0017 meters

this is actually the difference of two radius,

let say first radius r1 = 0.25 meters

second r2 = 0.25 + 0.0017 meters

rpm of the rotating system...

Caculate the reaction force of a radially moving object]]>

This device: https://researchfrontiers.uark.edu/good-vibrations/ from University of Arkansas

A free floating graphene sheet extracting energy from brownian motion and converting that to electric...

Vibration Energy Harvester from Brownian motion]]>

am I on the right lines ?]]>

I have a problem understanding what happens when a plane electromagnetic wave hits a surface consisting of two medias of different optical density.

My old school litterature tells me two formulas which I really don't understand where they come from.

The same teacher starts by telling me...

Refraction formula confusion]]>

Microwave oven door]]>

CMB and the reference point for vacuum energy]]>

Should we consider the Ultrasound or we should concentrate only on sound level in Air as frequency ultrasound have no effect on sound level?]]>

From one side, HR is described as a "reactive element", used in several contexts to attenuate a specific noise by means of...

Helmholtz Resonator: attenuation vs. amplification]]>

I am a Mechanical Engineering student but I am a TA for an electricity and magnetism course, and I had a student ask a question that's a little bit outside my understanding. The question was related to the equation for a radiating electric field from an accelerating charged particle:...

Relation of EM radiation equation to radioactive decay]]>

got a little problem i'm currently working on and looking for some input/sanity check.

Firstly i have a round tank within a round tank both with open tops, the inner tank is suspended within the outer tank such that there is a gap between both tanks bottoms faces, the inner tank open...

Density Siphoning?]]>

need to calculate the impact force done by the ladder to the head explained in the drawing. Can anyone help?

Kyrre]]>

2) a = rα and ##\vec a## = -##\frac{v^2}{r}####\vec e_{rad}## + rα##\vec e_{tan}##

Where ##\vec e_{tan}## is the unit vector along the tangent in increasing direction of θ

And ##\vec e_{rad}## is the unit vector along the radial...

Question about circular motion and acceleration]]>

I have come across this formula, but i haven't seen it before. What is it used for?]]>

Due to limited resources at my hand (my school doesn't have too much resources), my condition is somewhat like Raman, and hence I want to do the original experiment that...

Experimental Demonstration of the Raman - Nath Effect]]>

What's the restoring force, if there's a mass on a string?

mg

m

m/g

– m

– mg

I know F=-kx and that F=weight and weight=mg. But i dont know which answer is the correct,]]>

SHM Basics -- Series and parallel springs, conceptual question]]>

Heat never spontaneously pass from colder to warmer body

Total energy quality decreases in all processes.

Energy disperses

But what is it exactly? What is the correct description of the 2nd law of...

Correct statement of 2nd law of thermodynamics?]]>

Hi! The diagram above is showing a man swinging a swing (a facility you can find in playgrounds) back and forth. I'm trying to come up with a concise expression in words that describes the angle noted as theta so that I can write a clear and effective research...

How should I express this angle in words?]]>

thanks in advance]]>

I try to understand how it is possible with 3kW. Thank to yours ideas and attention.

Have a...

Quantum Laser Sintering]]>

Gauss' Law for electromagnetic radiation?]]>

am confused on where the gravitational potential energy is in this solution. Thank you]]>

I'm trying to measure the stray capacitance in a circuit comprised of an rf signal generator, an oscilloscope, a coaxial cable (short-circuited) and some capacitors. I measured the resonant frequencies of the coaxil cable for varying values of capacity (0pF to 850pF) between 4MHz...

Stray/Parasitic Capacitance - Impacts phase velocity?]]>

Considering a point at the top...

Water pressure in U-Tube arms]]>

1. Papers

Recent Noteworthy Physics Papers]]>

Is it even possible?]]>

i think its heating oil and pumping it around the building.

could it burn natural gas and just pump hot air through the furnace?

anyway. its slowing down my WiFi.]]>

In nuclear physics, the mass excess is caused by the nuclear binding energy.

Question: is there any macroscopic example where the "mass excess" is non-negligible?

Thank you for your time.

Regards.]]>

Highly collisional yet low resistivity plasmas]]>

My question:...

Shape of infinitesimal volumes]]>

i'm finishing my final degree project, it's about a new type of pallet conveyor dragged by magnets.

I know for a fact that magentic force is inversely proportional to the distance squared, and i've designed and built my prototype with that in mind.

Now i'm writing my final report and i need...

Need references for magnetic force vs distance/angle topic]]>

Does the coefficient of restitution depend on the collision being performed?

Consider two masses ##m_1## and ##m_2##. They are placed on a frictionless horizontal table and ##m_1## is given an initial velocity, collides 1-dimensionally with ##m_2##, and the...

Does the coefficient of restitution depend on the collision "type"?]]>

I'm investigating in using a dieletric barrier discharge for gas treatment, if I have two electrodes isolated by dieletric and the discharge gap between both of them has AIR..

how the ionization of air will take place, from where the source of electron which is going to start the...

Mechanism of discharge in DBD? (dieletric barrier discharge)]]>

Adding a constant to potential energy doesn't change action?]]>

Relative speed when someone runs on the treadmill]]>

I’ve been learning some kinematic equations and have been doing pretty well calculating acceleration. The issue I’m having is this. I found this tutorial...

How to calculate velocity based on distance and time?]]>

Formulas describing fluid viscosity/compress-ability]]>

Cooler objects able to increase the temperature of warmer objects?]]>

Relation between centrifugal force and speed]]>

creating waves in a pool 90 degrees off and out of phase by 90 will make it move in circles? I'm skeptical, anyone have a video of an experiment that demonstrates this?]]>

I’m not looking to solve this problem...

Angular velocity]]>

The Homopolar Generator: An Analytical Example

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The Homopolar Generator: An Analytical Example - Comments]]>

If we are stretching a a 3d rectangle

L is hight

A,B are the length and width

Starching it in the L direction so thats the longitudinal strain we are making

Why does the transverse strain in the "a " side equals the strain in "b" side

So like that we can both use ∆a/a or...

Poisson's ratio]]>

1. What are the higher rank tensors with physical meaning attached to them? I know tensors up to...

Questions about tensors]]>

Foucault pendulum and a round globe]]>

Why is blackbody radiation continuous?]]>

According to this document it would...

How To calculate the Power required for a Superconducting Magnet]]>