Concept Definition and 1000 Threads

Since I understood that torque = net moment, and as it said angle from the vertical, I used the equation t = F*d*cosx. So, 6 = 40*0.4*cosx, x = 68 degrees. I got a zero out of 5 in this question because the thought process was wrong as well as the answer. I do not understand this problem beyond...

seeking help for clear concept

In the textbook Electrochemical Systems by Newman and Alyea, Chapter 14: The definition of some thermodynamic functions, chemical potential of component (ionic or neutral) is written as a function of absolute activity: $$\mu_i=RT\ln(\lambda_i)\tag1$$ where ##\lambda_i## is the absolute activity...

I'm sure everyone here is aware of the hazards of orbital debris, and the difficulty of removing it. Lots of concepts have been proposed to help address it, but not many tests have been executed so far, mostly on larger debris like whole satellites. But what about the smaller stuff? Stuff that...

Not sure if it is meant to be a pump or a compressed air motor. Or maybe it can work as a pump or as a motor? What would be the practical problems? Does it add anything to the prior art? --- Edit : Not sure how it will make a proper seal, with that step in the back plate.

Consider the attachment below; How did they arrive at ##F_X (u) = \dfrac{u-a}{b-a}## ? I think there is a mistake on the inequality, probably its supposed to be ##a≤u<b## and that will mean; $$F_X (u) =\dfrac{1}{b-a} \int_a^u du= \dfrac{1}{b-a} ⋅(u-a)$$ as required. Your thoughts...then i...

It is argued that the correct interpretation of Newton's 2nd Law for one body of mass ##m## reads "The dynamics (i.e. vector sum of all external forces acting on the body = "all its interactions") dictates the kinetics (i.e. time derivative of the momentum vector = "motion")", under the...

My field is physics and I'm very cautious about the "math describing the Nature" attitude, but I can't help admiring the deep richness of mathematics! The other day, I was checking about isotropic tensors. An isotropic tensor keeps its components in all coordinated systems transformed under...

All the Geography/Geomorphology books I have come across with, simply write “Himalayas are fold mountains”, “folding is the warping of land due to tectonic motions”, “earth surface is like a dough which can be warped by compressing forces”. I mean, every time I fell on ground I never felt...

Hi PF. I desire deeper understanding of fundamental physics, and quantum mechanics can be a challenge for me (compared to other topics in physics). I read in the intro of the physics textbook chapter that QM explains many phenomena, e.g. why copper conducts electricity and glass does not. In...

Canonical ensemble can be used to derive probability distribution for the internal energy of the closed system at constant volume ##V## and number of particles ##N## in thermal contact with the reservoir. Also, it is stated that the temperature of both system and reservoir is the same, i.e...

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Hello, I am trying to clearly understand the concept of bandwidth. Let's assume we have two type of cables and a signal ##x(t)## that travels a distance ##L## along each cable. The first cable has bandwidth ##BW1## and the signal has speed ##v1## along it. The other cable has bandwidth ##BW2##...

Summary:We propose a search for low mass dark matter particles through momentum recoils caused by their scattering from trapped, nanometer-scale objects. The Paper linked details a novel concept for detecting WIMPs. I hope to see more work performed on the idea in the future...

We define differentiation as the limit of ##\frac{f(x+h)-f(x)}h## as ##h->0##. We find the instantaneous velocity at some time ##t_0## using differentiation and call it change at ##t_0##. We show tangent on the graph of the function at ##t_0##. But after taking h or time interval as zero to find...

Hi, PF Here is the text I've taken a look at file:///C:/Users/usuario/Desktop/2001_JMT_Girep.pdf And the article I'm looking for: Artigue M. and Viennot L. Some aspects of students' conceptions and difficulties about differentials, Misconceptions and Edu. Strategies in Sci&Math. Cornell...

Would any member of math help board prove highlighted 1 and 2 by simple and clear explanation with examples?

I have tried to solve a problem about the amount of watts a motor needs to recive if i want an elevator of 1250Kg to move at a speed of 2m/s +/- 0,10m/s after 3 seconds. The motor has an efficiency of 0,80. I've tried looking at my teachers uni recording, but it doesn't seem to explain this part...

I was watching this video that I found on Youtube. My question is, does type of electrolyte affect the voltage reading, since it dictates which redox reactions are possible? (here, Na2SO4 instread of CuSO4) Consider a Mg|Cu electrode pair in a galvanic cell; the reaction is, usually in...

With the latest view that free space has virtual particles constantly popping in and out of existence, is it now rational to argue that light can electromagnetically travel through free space for ever and ever without the slightest energy loss? Edwin Hubble found that the general red shift of...

I am confused by the concept of space-time in special relativity, I have 3 spatial dimensions and 1 time dimensions. In Newtonian physics don't I also have 3 spatial dimensions and 1 time dimension? Then why call it space time in special relativity and not in Newtonian physics?

Here is the picture (THIS ISN"T A HOMEWORK QUESTION JUST WANT TO UNDERSTAND A CONCEPT) I don't understand isn't the tire pushing forward not backward becuase of the friction, road is pushing back.

Assumptions: There is no "absolute" time, time is all relative. Taking the twins paradox as an example, both twins measure a different proper time when they re-unite due to each twin taking paths of differing lengths through spacetime. Conclusion: Time Travel itself is a completely...

Hi guys i have some concept issues about flux. My book says flux is proportional to the number of lines passing through that area. so my question is: first i am thinking that a 2D circle which has a 2r diameter and it is enclosing a 2q charge so its flux should be 2q/Epsilon.then i am thinking a...

-1st: Could someone give me some insight on what a ket-state refers to when dealing with a field? To my understand it tells us the probability amplitude of having each excitation at any spacetime point, but I don't know if this is accurate. Also, we solve the free field equation not for this...

As a follow up from my other thread, where I consider popular media describe entanglement sort of as: and I think this may be wrong. As a follow up question I want to put forward this: A singlet state of entangled particles is notated in a superposition of product states as: ##|up, down...

Phi= int(E.da) through a surface S is a measure of “number of field lines” passing through S. I put this in quotes because of course we can only draw a representative sample of field lines. The total number would be infinite. But for a given sampling rate the flux is proportional to the number...

Given two subspaces ##U_1, U_2##, I understand the concept of direct sum $$ W= U_1 \oplus U_2 \iff W= U_1 + U_2, \quad U_1 \cap U_2 = \{ 0 \}$$ Where ##W## is a subspace of ##V##. I am trying to generalize it for more than ##2## subspaces, say ##3##. I thought of the following. $$ W= U_1...

Hello everyone. How are you? I want to learn calculus so badly. I plan to do a self-study of calculus l, ll, and lll. Before thinking so far ahead, I need a clear, basic definition of the concept of a limit. Textbook language is never easy to grasp unless the student is gifted. I am not gifted...

Hi everyone! =) . I'm having some issues with this exercises, It's about functions. I remember the basic geometrics formulas and how to get the area and perimeter of a square or a circle but I don't get it. I need an explanation. 1. Express the area A of a square as a function of (a) the length...

In the TIL thread, I posted a link which had a number of imaged of an early proposal for the Apollo program. I thought I'd use them to do a few renders of what it might have looked like, and point out some of the major differences from the final version. First, what the craft in fully...

I've created a concept design of a subsea pumped hydro storage system, and need to use the flow rate in order to calculate power output. I can calculate the energy storage capacity using ##E = mgh##: $$E = mgh = 25675000×9.81×200 = 50374 MJ = \frac {50374MJ}{3600} = 13992 kWh$$ I've attempted...

Under plane stress (z direction perpendicular to the plane), there shouldn’t be any z stress component. Then if one end of the 2D model is fixed, does that mean the displacement on that fixed boundary is completely zero (u=v=w=0), but that will generally violate the stress component along z being 0.

Hey I am starting a course on plasma physics, I don't understand the principle of Stellarators. If there is no plasma current, how is the mhd equilibrium achieved (J \times B = grad P)? I apologize if the answer is obvious, but I starting with this

Hello Everyone! this question is using Indonesian language, i have translated the question at "Homework Statement". The container is filled by water (in Indonesian, "Air" means "Water") i know the the pressure at point X, Y and Z depends on their corresponding depth. my best answer is : Pz >...

I think: Due to charge q, there will be a field in region 1, very much dependent on position of q. The inner surface charge density of irregular conductor is also dependent on the position( so that it could cancel the field of charge and E=0 inside body of irregular conductor). The outer...

Summary:: Ideas for a novel I want to begin writing. Brainstorming ideas and need help with a certain concept. Any help is appreciated! Hello to you all, this is my first post, and I Google searched this astrophysics forum because I thought it might be a good place to begin asking for advice...

is the concept of potential just a mathematical model

I am curious about time traveling. According to Einstein's special relativity, the easiest way to travel into the future is by approaching the speed of light or faster. Now assume this setup: Sunlight travels to Earth at c (speed of light). We have the technology to reach speeds faster than...

I know the procedure to construct Nyquist plot and check the stability of the given system. But I am a bit confused about the concept of encirclement in the argument principle. Consider the following figure. This is the Nyquist plot for the given open loop transfer function. The Nyquist contour...

Let's consider the Taylor power series of a function on real numbers. Some of them represent elementary functions, and some of them represent special functions. The special functions cannot be expressed via finite combination of elementary functions on real or complex numbers. Now, take some...

I don't have the requirements (thorough knowledge of SRT, ART etc.) to get into this theory, but I would like to get an idea about this word. For the simplest case of a one-dimensional string, it is compared to a string from a musical instrument. Now the question is, what this string should...

Such particles are virtual, but it should be possible to associate a basic idea with them, as this is the foundation of calculation methods. I think the concept of vacuum fluctuations in the form of virtual, fluctuating pairs of particles is something else. Is the idea of virtual exchange...

Hello Forum, Energy, like space and time, is a common concept but little understood. I think Feynman himself stated energy is hard to describe... I have a few observations in regards to energy and I would like your feedback on them: While force, which represents an interaction between two...

Has anyone come across Quine's New Foundations? https://plato.stanford.edu/entries/quine-nf/ https://en.wikipedia.org/wiki/New_Foundations I'm not very knowledgeable about set theory, mathematical logic, or the foundations of mathematics, but I found what I read interesting. The basic idea (as...

Thought this might be an interesting question. Feel free to post why it was hard and/or what let you finally understand it.

I am reading a book on fusion and just went over a paragraph of magnetic mirror confinement. What I want to understand is this. So all charged particles gyrate around magnetic field lines and if they have also a velocity parallel to the field they form helical paths. The gyroradius is...

Hello can someone help me understand the difference between Spacelike timelines and the two others found in Carroll page 71?

I have a trouble showing proofs for matrix problems. I would like to know how A is invertible -> det(A) not 0 -> A is linearly independent -> Column of A spans the matrix holds for square matrix A. It would be great if you can show how one leads to another with examples! :) Thanks for helping...

Is concept of inertial vs non inertial frame inveted in Einsten theory of relativity or Newton knows that we can see on same object from different perspective? (Newton set 3 laws for inertial frame,so did he knew for realitivtiy when view object form different perspective/frame and did he...