I remember hearing/reading somewhere that the energy transmission in a circuit like...

How does the Poynting vector factor into a normal circuit?]]>

How to do the Dark Frame Subtraction?]]>

For all intents and purposes, it appears as if a superconductor suspended above a magnetic field is defying gravity. I understand that there is no work being done (as...

Is there energy associated with flux pinning?]]>

I'd like to understand how filling my butane lighter works from a more rigorous point of view than just guessing.

How I can tell when my refill cannister is getting inefficient? (i.e. more rigorously than just shaking it or weighing it) I hope to detemine how...

refilling butane lighter the physics way]]>

$$dS = dQ/T$$

Adiabatic Invsicid

$$dQ =0= dS$$

So no heat added or lost no change in entropy I'm fine with that...

Why is Bernoullis Isentropic]]>

I understand for the lift factor with the example of blowing air over the...

Faster velocity of water in tunnel Decrease in pressure?]]>

Current through Thin Wires]]>

What is actually happening to a charge in a magnetic field?]]>

Efficient Fast Orbital Transportation/Construction?]]>

...

Image formation in concave mirror]]>

Comment 2 says that resultant force is opposite the motion but I have some hesitations about it because let's think the situation that mass is moving back upward to its equilibrium...

The Sense of Restoring Force in Vibrations]]>

Question about Work]]>

The heat equation, change in concentration or temperature is equal to the average of its neighbors...

why is the wave equation different from the heat equation]]>

A spaceship orbits Earth at 300,000 km distance at speed 0.5c broadcasting live images of the clock aboard, will the clocks difference will be 1 sec?

The orbit is a perfect circle.

Its moving close to the speed of light but stays at the same...

Near-light speed and time]]>

Why doesn't a charge repel a magnetic field in this example?]]>

Shorting of a capacitor]]>

So entropy is given by S= k ln W. where W is the number of microstates of a system. Know let's imagine there is a box containing a number of gas atoms let's say the gas atoms have a current position and velocity and say you can...

Microstates kT and entropy]]>

Why would a parallel circuit(or in blood) decrease resistance?

Here is my thought experiment and where I got stuck:

Say from aorta to one arteriole, the resistance is super high on that flow(this big amount of flow is entering a tinier area), but add more arterioles and we...

Why would a parallel circuit (or in blood) decrease resistance]]>

Cheers,

Glenn]]>

How many state changes per second could optical computing do]]>

Thank you]]>

Trust me I'm a Photographer -- I have a question]]>

black holes had such gravity as to have an

escapr velocity higher than c, which means that

things are pulled inwards at higher speeds than

the speed of light. Or am I overlooking something?]]>

Duration of sound in our brain (0.1s)]]>

First stop should be our very our PF Insights blog which hosts many physics tutorials...

Physics Learning Resources]]>

The Problem Statement

I have a jet entering leaving a nozzle at u

I am trying to equate the rate of momentum diffusement (or spread)...

Jet Spread Rate K Values- Momentum diffusement]]>

Is it true, that only

How would you pronounce ħ?]]>

universal stationary frame of reference for speed, d and t]]>

I understand that

Explaining the Hierarchy problem for beginners]]>

Experimental investigation of c in electric & magnetic fields]]>

1. Papers

Recent Noteworthy Physics Papers]]>

Please critique the following logic...

When a runner hikes/runs to the top of a mountain, the chemical potential energy inside the muscles transferred into the potential energy of the runner's body mass at the higher elevation (Pe = mass*gravity*height = mgh). Energy is...

Energy transfer during uphill vs downhill running]]>

F_{B} = ρ_{DF} × g ×V_{DF}

Buoyant Force and what densities to consider?]]>

Deriving the progressive mechanical wave equation.]]>

What are the missing ingredients? The answer is the boundary condition .With appropriate boundary conditions, zero divergence and zero curl will nail down a unique solution...

Zero divergence and zero curl]]>

https://en.m.wikipedia.org/wiki/Magnetic_field

Why is in the definition the way it is Generated?

When we had...

The right definition of magnetic field?]]>

Circular motion in a cone]]>

Why the photon has no mass?]]>

EPQ help (slingshot)]]>

So lets think that we have rail and we move

Somekind batteries in this rail

and we have also solar elements to get energy to power

this rail system and a lamp to throw out enregy from this

thing that we move. And what we move is...

Move vehicle in space by rail structure systema]]>

A ball struck by a cue in billiards with English goes straight at first...]]>

I imagine myself as a wasp-sized human. I...

Why doesn't the wasp die when I hit it with a fly swatter?]]>

There is a pendulum suspended on an arm that rotates a certain angle in the horizontal plane. The arm suddenly stops, how far will the mass of the pendulum be displaced in the horizontaly?

Thought so far:

The momentum of the arm will be L=IW and when it stops I think the mass at the...

pendulum on a rotating arm]]>

I’ve been trying to derive Posseuille’s Law and I’m very close. However there seems to be a small difference between my concluded formula and the real one but I don’t know why.

Here’s what I get:

Picture a cilindrical tube with a radius ##R## in which a fluid is flowing. From what I...

Deriving Posseuille's Law]]>

Is this possible?...

Magnetic field direction on Halbach array?]]>

I have found this:

https://en.wikipedia.org/wiki/Electret

Do you know this materials? Is it possible to purchase some electrets in a store?]]>

A little question bothering me concerning elliptical trajectories:

Say I have a particle at some point with some velocity (both I know - r0, v0) and I need know its minimal velocity so that it reaches some specific r*.

I can easily find this velocity considering conservation of...

Velocity in eliptical trajectories]]>

Like F=Gm1m1/r^2 and F=kQ1Q1/r^2

Thanks]]>

Lets think we have two batteries or something similar

spinning in space like in carusel structure.

And the batteries are athe more spinning end.

First the batteries are empty and we start loading

the first battery.

So em i...

Two very basic questions about momentum in space]]>

I have an equation I'm trying to work out if it 'Laplaceable'?

As in, can I get a transfer function?

d

The direction of Force?]]>

I have a question related to a specific situation.

I've been playing a game called Overwatch and while I'm not the smartest there is in physics I'd like to understand it better.

In Overwatch there is a character named Roadhog he wields a shotgun and a hook.

Using this hook he can launch...

How do I calculate the G Force in this certain situation?]]>

--

lightarrow]]>

1. Energy is a system's ability to do work.

2. Work is force over a distance.

3. A force is applied over some distance.

4. All physical change (i.e. all change in a system through its phase space) is the result of force.

∴ Therefore, energy would seem to be a system's ability to...

Help Understanding Energy in General]]>

In this experiment a 1/4" ball bearing of various metals is being translated over the glass surface under a constant load of 2000g. The glass slide is...

Calculation of friction stresses between 2 materials]]>

Consider the circuit in figure, moving in a time ##dt## in a magnetic field ##B##, constant in time (but not...

Flux through rim created by moving circuit and induced EMF]]>

Black holes and time]]>

Interesting experiment about the attraction between two magnets]]>

Example 1: An elevator

Suppose an elevator...

Inertia (and, to some extent, circular motion again)]]>

My problem is that this setup only records data in one plane...

Correcting results to fit Rutherford's Scattering Formula]]>

1)Can use noise a generator?

Well , if we have a noisy resistor and Ideal resistor why can't we use noise voltage according to noise voltage [tex]Vn=\sqrt(4KTBR)[/tex]

2)why we...

Some questions about Noise and Power spectral Density]]>

The solar system is orbiting the galaxy's central black hole, so, if you push a satellite in 1 direction while it attracts to Earth it will orbit Earth but should be left behind big time still.

Also, if we were to place...

If Earth moves at 500,000 mph then why don't satellites stay behind?]]>

The other has a Mass of 4kg, and velocity is 0m/s. ( at rest)

1) Energy cannot be created or destroyed. (Energy is conserved)

2) Momentum is conserved.

Total Momentum before was (2x5) +...

Inelastic Collisions in space]]>

Boltzmann's constant validity domain]]>

Suppose that I want to calculate the magnetic field ##B## at a distance ##r <...

Magnetic field due to displacement current and Ampere's law]]>

Has anything in the universe ever reached 0 Kelvin?]]>

Let's say humanity could concentrate all of its resources to create a perfect vacuum (neutrinos, photons etc don't count, it only has to be...

If you had to make a perfect vacuum, version #2]]>

My book states that solar cells are joined in series and in parallel to give a greater power because P=VI is increased by increasing V and I.

I assume that the...

Arrangement of solar cells]]>

time travel/speed of light]]>

I have a somewhat dumb question. It is based on the fact that I can create a small vacuum in my mouth to move that "string" of spagetti into my mouth.

I know it is possible, but I do not understand how spaghetti is possible to suck in if the shape is even and round like a "piston".

I...

Vacuum or pressure to move spaghetti through a hole]]>

understanding the force between two objects]]>

Instrument Line Function of a Spectrometer]]>

Similarly some metals reflect some frequency but absorb some. How atomic orbitals play...

EM wave penetration through walls...]]>

Lastly, is the online reasoning for why we can't hear sound as well underwater correct: the water vibration bypasses some of the sensory...

Sound underwater distance and decibels]]>

Gallium not becoming a solid again?]]>