1. A weight hangs from a spring. If a force is applied to the weight at

Trig function equation: d=4(sin5t-4cos6t)]]>

This is more of a general question, not specific to any problem. I am not too good at drawing force diagrams so I was hoping I could post an image and get some guidance on how to find the forces acting on the object.

In this...

Force Diagram Drawings]]>

Is it normal for professors to allow cheat-sheets in tests?]]>

Hello!

To those who are reading this post, I need your help! I’m sure I will find here experienced and skilled people willing to give me a hand with this project.

First, I’m French, and even if I’ll do my best to...

Audio Streamer for Hearing Aids]]>

This is my first post on this forum, but most certainly not my last. I am relatively new to physics. I mean, i understand the basics. I would like to make it my hobby. You know, really find a passion for the physics. BTW, i am from the Netherlands, so please do not...

Twin spring system with a mass in between (X and Y direction)]]>

Lee Smolin and several others (Cohen, Cortês, Elitzur) have published a pair of related papers discussing dBB/Bohmian Mechanics and its...

A retrocausal amendment to de Broglie-Bohm pilot wave theory]]>

The potential difference across resistance R carrying current I is V = IR . Now if the potential difference is measured via voltmeter of resistance r , the reading on voltmeter is V' . Prove that V' = Ir/(R+r) . For what...

Reading of voltmeter having resistance r across a resistance]]>

But in another frame of reference, that is moving with velocity v relative to first frame of reference, they feel both magnetic and electric force...

Moving charges in a moving frame of reference]]>

But, how does a Mathematician reconcile itself with the idea of random? There's no...

What's the meaning of "random" in Mathematics?]]>

After my theoretical post on vacuum diode electron flow, I decided to try and measure it physically. I didn't have a vacuum tube, so I improvised with some tungsten wire, aluminum sheets and some...

Measurement of vacuum diode electron flow]]>

I don't understand this notation, regarding the use of the semi colon, is it...

Meaning of the Riemman Tensor notation in the choquet Bruhat]]>

In the far future, humans have built a space elevator as a cheap

means of access to space. However before that could be done, a few basic principles had to be

worked out. . .

a)

What is the minimum initial speed (in an...

Space elevator minimum initial speed]]>

I am reading about the capacitors. I have read that the capacitors block DC and behaves as open circuit in DC while short circuit in AC. The reason behind this is the charging and discharging of the capacitor. What is my perception about it, I will mention about it.

"

During the DC...

Capacitor Noise Removal ?]]>

How does mechanical torque affect generating volts and amps?]]>

atom can exist in only 2 states. The ground state is an s state and the excited state at

1.25 eV is a...

Statistics physics problem]]>

where "ln" is natural log, a and b have variable values in them.

View attachment 239212 View attachment 239212 View attachment 239212]]>

A 23 kg solid door is 220 cm tall, 95 cm wide. What is the door's moment of inertia for rotation about a vertical axis inside the door, 17 cm from one edge?

I = I_cm + MR^2

Moment of inertia of door rotation]]>

The system of masses M

View attachment 190402

Three mass pulley system]]>

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I want to get both the resistive ## R_o ## and the reactive ## X_o ## components of the output impedance ## R + jX_o ##. Measuring the open circuit voltage will give ##V##. If I connect a...

How to measure the reactive part of output impedance?]]>

Some...

Older electrolytic capacitor testing]]>

1)...

Need help in regulating +/-36V regulated supplies.]]>

I was told every country needs a constant electricity production source (like coal or nuclear powerplants), and up to some proportion, renewable sources (photovoltaics, hydro, wind turbines, etc).

So, my question is: what limits the amount of renewable sources? (the grid, storage...?)...

What limits the amount of renewable energy sources?]]>

Entangled Particle Detection]]>

Like in 3 dimensional cube, you have squares as faces and between them there is a space.

But in tesseract where you have 8 cubes as faces, this leaves 0 space for actual space inside, i can see only 8 faces and nothing between them.

I first thought it...

Where is the actual space inside a tesseract?]]>

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For the observer in the cloud, the parallel light has traveled 2.294cs, but this is only 0.23cs in front of the ship. 0.23 cs is only 0.086cs in the...

Relativity Paradox Help]]>

A researcher from Texas Tech University presented her findings at the recent AAAS Meeting, and found that most people started to believe in the Flat...

Is YouTube Responsible For Creating Flat-Earth Believers?]]>

So, I guess we all know how that space-time fabric is bended by gravity. When a star dies, all of the atoms are brought extremely close...

Could singularities be just rips in the space-time fabric?]]>

Im making a tool for polystyrene sculpting using nicrom wire and 2 batteries, however the heat is take by the cooper wires and go to the batteries which is not recommended and also not energy efficient. Any idea?]]>

Basically my PhD is in mitochondrial biology. Mitochondria are the energy producing organelles in the body which make energy by adding a chemical bond...

A physics perspective needed on how the Mitochondria machine works]]>

$$\vec{\mathbf{A}} \times \vec{\mathbf{B}} = (A^T \cdot J_x \cdot B) \>\> \hat{i} + (A^T \cdot J_y \cdot B)...

Relation Between Cross Product and Infinitesimal Rotations]]>

How to introduce a phase shift in an AC circuit]]>

Confusion about absorption spectra - cool gases absorb?]]>

Turns out that Zoobyshoe beat me in posting about this in another thread, so he will officially be known...

Weird News Compilation]]>

$$W=\int Fdr$$

$$W=\int \frac {dp} {dt}dr=\int (dp) \frac {dr} {dt}=\int (mdv)v=1/2m[v_f^2-v_i^2]$$]]>

I am suppose to determine if the following rule is a distribution $$\langle u,\phi \rangle = \int_0^1 \frac{u(x)}{x} \, dx$$ and then also $$\langle u,\phi \rangle = \int_{-\infty}^\infty \phi + 1 \, dx.$$ The notation is throwing me off. At first I thought I had to show ## \langle Au +...

Distribution Notation]]>

I need to add...

Force and Torque Calculation and Observation]]>

A cylinder with a mass of M and radius R is attached to a spring with a constant of k. The attachment always stays the same as described in the picture. The cylinder is moved to the right and the released, and it rolls without...

Where is my mistake? (Pure rolling and center of mass)]]>

i.e. blue-shifted or red-shifted, depending on its path?

(I guess the light would be acting as the third body in a three-body system?)]]>

I am trying to get my head around the important difference between these two different styles (paradigms) of programming. I am familiar with traditional structural programming: data, variables, functions, structures. The functions are blocks of instructions that can process data, etc....

Object Oriented Programming vs Structural Programming]]>

Calculating the number of energy states using momentum space]]>

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The work builds off of previous work, which had expanded the genetic alphabet to...

Researchers double the size of the DNA alphabet]]>

Intro to thermal Physics - D. V. Schroeder -Entropy question]]>

New member]]>

https://www.springer.com/la/book/9783030043599

It looks like it covers a lot of material, and I'm wondering what people here think of it, especially the chapters on quantum theory.]]>

Which Tally type should I use in MCNP6?]]>

Is anyone familiar with the technique of compressive sampling? I am trying to grasp how it works, its strengths, etc. It is a way to decompose signal and reconstruct them from fewer information than the traditional transforms (Fourier, etc.) or compressive algorithms...

Thanks!]]>

Determine whether the given series is absolutely convergent, conditionally convergent, or divergent.

##\frac{1}{3} + \frac{1 \cdot 4}{3 \cdot 5} + \frac{1 \cdot 4 \cdot 7}{3 \cdot 5 \cdot 7} + \frac{1 \cdot 4 \cdot 7 \cdot...

Convergence of a series given in non-closed form]]>

Here's my list:

- Texas A&M Cyclotron -
*Accepted 2/22* - Duke TUNL
*(first round offers...*

2019 REU/Summer Program Acceptance Thread]]>

The angle alfa has its vertex at a point O, from one of its sides the point M is taken from which the perpendicular to the other side is made with the point N. In the same way, from the other side point K is taken and from there...

Geometry, finding a segment.]]>

My attempt at this question: FS2 - FS1 = 6000 - 5400 = 600N

But I'm having...

Diving Board Torque with No Given Mass of Diver]]>

I've been doing some worldbulding lately and I came up with this idea of a world in which civilisation and life are much, much older than in ours. Yet it isn't as developed due to some kind of natural disaster...

World destroying solar storm/binary orbit]]>

Consider a naked human body, with a surface area of 1.5 m^2 and an average temperature of 30° C (skin temperature), that stands at the middle of an empty breezy room whose surfaces have a temperature of 10° C.

Assuming the...

Why is the Stefan-Boltzman formula for this problem like this?]]>

For a constant power signal x(t) = c, determine the auto correlation function and the spectral density function.

The auto correlation function is:

$$R_x (\tau) = \int_{-\infty}^{\infty} E(x(t)...

Autocorrelation and Spectral Density]]>

Would there be an upper limit to density in QM?]]>

I'm just curious, say if a billiard ball just suddenly started moving without any other object making it do so, (kinetic energy was created), if it also suddenly...

Conservation of Energy Question]]>

where the normal mode frequencies are defined by the eigenvalue equation:

$$ M \omega^2 \epsilon = D(k) \epsilon $$

The volume of the crystal...

Gruneisen Parameter]]>

Our Beautiful Universe - Photos and Videos]]>

and the following discussion? It also includes links...

Exceptional Quantum Geometry and Particle Physics]]>

Here is the last page of part 5.

https://www.physicsforums.com/threads/random-thoughts-part-5.851969/page-134]]>

Figure shows a potentiometer circuit for comparison of two resistances , the balance point with standard resistor R = 10 ohm , is found to be 58.3 , while that with unknown resistance X is 68.5 cm , determine the value of X .

b)...

Calculating resistances via a potentiometer]]>

https://iopscience.iop.org/article/10.1088/1361-6404/aaa032

Does the author say anything that is...

Visualizing quantum fields]]>

If gear 1 fits into the internal gear and is made to rotate, will the internal gear rotate with gear 1?

https://imgur.com/gallery/ELYZoRb]]>

Do five positive integers exist such that the positive difference between any two is the greatest common divisor of those two numbers?

I found four such...

Number Theory Problem: difference between any two integers is the greatest common divisor...]]>

The short story is that I'd like to go through university level maths and physics because:

- I like maths and physics

- Deepening knowledge of maths would be useful in my programming career

The longer story is that while being a kid, I loved...

Maths and physics books for undergraduate level self-study]]>

Shielding a wire from magnetic flux]]>

Volunteer/unpaid work to build skills]]>

Colliding PP waves and nearly colliding BH's]]>

And...

"Define" ℕ from ℤ or ℝ from ℂ, etc...]]>

It wasn't Faraday, who apparently coined the terms "anode",...

Name of a scientist who introduced many words into English?]]>

Find the useful denial of a injective function and a surjective function.

I know a one to one function is (∀x

Finding a useful denial of a injective function and a surjective function]]>

My wife just drew this

View attachment 93241]]>

Google does not give me any links except to explanations of the Lorentz force law.]]>

How much more innocuous can a topic be to focus on something so mundane as a hook? But that is the theme of our contest this week. The hook can be of any size. It can be a grappling hook of a crane, all the way down to a hook on a fishing line....

PF Photo Contest - Captain Hook (2/16-2/22)]]>

I am searching for an explanation that connects the mean squared displacement in an ensemble of particles to the velocity autocorrelation functions. I know that they are connected since both of them can be used to calculate the diffusion constant. But I do not find a mathematical...

Equivalence of msd and velocity autocorrelation]]>

Hello there,

This is my first post, I find myself often wondering about the universe and how it works, and there are a couple of things I just can't wrap my head around.

According...

Understanding gravity: mass and gravity relation]]>

Is interdisciplinary engineering worth the money?]]>

I ask for solution help from the integral below, where y and x represent angles in a metric of a spherical, 2-D surface. He was studying how to obtain the geodesic curves on the spherical surface, the sphere of radius r = 1, to simplify. The integral is the end result. It is enough, now,...

Tips for solving an Integral (angles in a metric of a spherical, 2-D surface)]]>

To quantize the field we expand it in appropriate modes. The three sets of modes required are:

- The incoming modes,...

Quantum amplitude for a particle falling into a black hole]]>

Calculating the area of a circle or square using decimals]]>

In chapter 4.7.5 of "Thomson Modern Particle Physics" the charge conjugation operator is derived without changing the electromagnetic field...

Does Charge Conjugation change the electromagnetic field?]]>

Unfortunately a recent study found something like half of americans mistakenly believe flu vaccines can cause the flu....

Get your flu shot]]>

x = 192

y = 433

z = -453

I need to...

Find the Acceleration and Distance from the Output of an Accelerometer Sensor]]>

Magnetic field of a moving charge and Maxwell's equations]]>

I only learned the basics of Hamiltonian mechanics during undergrad and now those papers I read show very generalized version...

Textbook for calculus of variations? Hamiltonian mechanics?]]>

More precisely, That contain about:

Introduction about the birth of relativity and principle, and the transformation...

A question/suggestion of a book: integrated course of "special" and "general relativity"]]>