I was watching this video of veritasium today and was wondering why the aluminum plate doesn't oscillate when there is a changing magnetic flux. When the flux is increasing, the induced magnetic field (by the induced current) is against...Why doesn't a magnetically levitating conductor oscillate?]]>

On earth's equator, our tangential velocity is ~1700 km/hr. A satellite orbiting right...

Gravity, friction and tangential velocity]]>

In a rectangular shape that is tipping, Usually we take the center of mass as an axis of rotation however the center of mass is accelerating with centripetal force so taking it would make the problem complex and we just take...

Instantaneous axis of rotation]]>

I know the muzzle velocity only applies to the...

Finding a bullet's velocity over time]]>

Understanding Entropy and the 2nd Law of Thermodynamics

View attachment 178074

...

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

The validity of ray optics in telescopes]]>

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]]>

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]]>

In undergraduate school, I learnt that Gibbs free energy is "available" energy we can extract from system at constant pressure and temperature.

G=H-TS=U+PV-TS

In above expression, however, I can't understand why "TS term" is...

Meaning of Gibbs free energy?]]>

What causes disturbance on my phone camera?]]>

Restricted three body problem (numerical simulation of gravitational attraction)]]>

Where C = capacitance, ε0 is epsilons constant, K = dielectric constant, A = area of aluminum foil, and D is the...

Calculating how to make a homemade capacitor]]>

“The Classical Theory of Fields” – by Landau and Lifshitz, in its discussion about classical size of a particle, concludes that:- Thus we come to the conclusion that in classical (non-quantum) ‘relativistic mechanics’, we cannot ascribe finite...

Difficulty with a Point Charged Particle in Electrodynamics]]>

Typographical question: the section sign]]>

Light from Cherenkov radiation]]>

Lower limit in pair production]]>

Need help with a thought experiment about a Faraday generator]]>

However, the temperature of planetary surfaces without an atmosphere are often quoted. For example, the temperature of the lunar surface ranges from about -200 F to +200 F depending on whether or not the surface is exposed to the sun or is in shadow....

Temperature of Space]]>

In thermodynamics, we say: the amount of energy Q, can raise temperature of the liquid by the formula Q1=cm(t2-t1); when the liquid reaches the boiling point (100 C), we write Q2=Lm.

Q2 is entirely spent on changing liquid state...

Liquid boiling and Evaporation]]>

Heat vs agitation]]>

there is a whole website to make people understand it i read the articles and i didn't found any thing complicated

knowing the i am 13 so it should be very hard to understand]]>

Looking for some help on how to go about finding the natural frequency of a block of foam. The foam has a density of 0.37 lbs./ft^3 and is 48"x48"x8" (LxWxD) in size. Weight is approximately 5.4 lbs.

I have been digging around the internet for quite some time with no such luck...

Natural Frequency of a Foam Block?]]>

I have a semi-conducting sample which has been run on a PPMS system - measuring it's resistivity as a function of temperature.

I switched to AC transport mode in order to measure the resistivity again while applying frequencies between 1Hz -...

AC transport data query (using a PPMS system)]]>

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

Slipping: If P critical > Us N then it slips

What if we have P critical = Us N. Any increase will make it slide and tip...?

If we took a rectangular shape object with Height h and length L so half its...

How can an object tip and slip at the same time?]]>

There is a thing I struggle to understand on laser physics. There is a modulation method called direct modulation for semiconductor lasers where by changing the current we modulate the light which is emitted form the laser cavity. There is a picture below

View attachment 216711 ...

Direct Modulation and Photon Lifetime - Laser]]>

I was helping one of my professors...

Fun magnetics question with the Meissner Effect]]>

Could you explain these in layman's term,because I don't know much about quantum mechanics.]]>

Copper and magnetism]]>

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

I did the famous "Mass Lifter Heat Engine" experiment in which a mass is put at the top of a piston enclosed within a cylinder. The cylinder is connected to an aluminium canister of air and the air inside this canister expands and contracts the piston with thermal contact. We had 2...

Heat energy input from a hot source in a heat engine]]>

Is it possible for airplane radars to scan minefields?]]>

Energy is neither created nor destroyed. So dU = 0 for the universe as a whole.

If the universe is constantly expanding, then it must be doing work on the vacuum around it, right? So W is a...

Internal energy and total heat of universe]]>

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 hypothesis 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.]]>

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?]]>

See this image View attachment 216035

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

I will be thankful for help!]]>

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]]>

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]]>

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

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]]>