Explanation Definition and 982 Threads

1. Homework Statement An amusement park ride consists of a large vertical cylinder that spins about its axis fast enough that any person inside is held up against the wall when the floor drops away (see figure). The coefficient of static friction between person and wall is μs, and the radius of...

Was the concept of a White Hole ever intended to as a POSSIBLE explanation for the Big Bang, inflation and dark energy expansion of the Universe? Or is it considered crack pottery by the cosmology community? I presume the observable Universe would need to be as small as say a single atom in...

Has somebody a paper, text, (whatever), which explains the Lagrangian Coherent Structures ? I want an explanation by words and not all the mathematical stuff. All I can find about LCS is 1. They organize flow 2. you can detect them with the Lyapunov exponents. But I want to understand what LCS...

Hello, I am having a very hard time understanding exactly what a POVM is. Could anyone provide a simple explanation? Thank you

I'm having real trouble understanding some concepts in RLC circuits. If I have a circuit like this. The effective voltage is 120 V. What is the required frequency for resistor to release power of 250 W? I want to really understand this on a deeper level so please make the explanation...

I've got to explain how spin art works to some 5th graders tomorrow. Basic setup: Paper is attached to center of a horizontal disk. Paint droplets are placed at different places on the paper. Disk is spun which causes paint to produce a pattern flowing away from the center of the disk/paper...

I've learned that in a wire with a current flowing through it, a magnetic field is produced, and that to determine the direction of the fields, one could match their thumb with the direction of current and curl their fingers around the wire as shown in the link below. I also learned that in Biot...

Homework Statement See the photo of the problem in the attachment Homework Equations Bernoulli equation and continuity equation The Attempt at a Solution I don't know from where to begin , i only can get the velocity of fluid when it reaches the hole

I am not sure I understand exactly what was the situation was with the EPR paradox Example: for simplicity: two electrons are coupled. One with spin up and the other with spin down. Since they are coupled there are one state. Separate the electrons one in one galaxy and the other in another...

Can anyone explain intuitively or give a better explanation of multi gaussian beams and the ABCD matrix approach for sound (ultrasonics) and not light? Thanks!

could anyone explain me how is it possible to charge your phone wireless, like this video link?

I have tried to find the least confusing (or rather, the most 'deconfusing') explanation for why it is possible for a cart with a prop to travel directly downwind faster than the wind. So far this is what I've come up with: Initial discussion At first glance, a cart traveling down faster than...

I can't understand how this code was able to swap or get this output: Based off of the following code what is the output of the main function? void Swap(int& x, int y){ int temp = x; x = y; y = temp; return; } int main(){ int a =12; int b = 3; Swap( b...

Consider pure water separated from an aqueous starch solution by a semipermeable membrane, which allows water to pass freely but not starch. After some time has elapsed, the concentration of starch solution a. will have increased b. will have decreased c. will not have changed d. might have...

Do we yet have an explanation for the Measurement Problem that Einstein would have been satisfied with?

I tried to come up with a simple calculus-free explanation for why the energy in a sound wave is proportional to the square of the wave's amplitude for my musical acoustics class. I think this makes sense, and seems to just be an elaboration of what Donald Hall writes, but I haven't seen it...

Hi, I am wondering about latent heat release when water freezes but it seems best to start with a regular exothermic reaction. How does bond formation create heat? What is actually happening at the microscopic level so that these combining particles are capable of causing adjacent molecules...

In the paper Advanced LIGO they published some figures with chances. I would like to know how they know that there's a 90% chance for something to be in a specific value. https://dcc.ligo.org/public/0122/P1500218/014/PhysRevLett.116.241102.pdf paper here also have some other questions: What...

I'm reading an old book about Thales (Greek geometry), and I can't understand what the next part means, and how to represent it graphically, could you help me? thanks: It begin stating that if you divide an equilateral traingle with a perpendicular from a vertex on the opposite side, it'll be...

So say that I have the quadratic equation ##x^2 - 2x +1 = 0##. If I multiply each side by ##x##, a valid operation, I get the new equation ##x^3 - 2x^2 + x = 0##, which has a different solution set as the first, namely ##\left\{ {0, 1}\right\}##. If I make the substitution ##x^2 = 2x -1 = 0##...

Recently I can across this proof: 0/0= (100-100)/(100-100) = (10^2-10^2)/10(10-10) =(10-10)(10+10)/10(10-10) = (10+10)/10 =20/10 = 2 But this is obviously wrong, as 0/0 is infinity, but which line in this proof is actually wrong?

So I'm working through a physics a textbook on my own, and because of that don't always have a professor who can help explain concepts I don't understand, so I'm turning to you good folks. Could someone explain why both masses need to be taken into account when determining the acceleration of...

Once again, I came across the notion (in a lay physics book by an academic) that two mutually exclusive states simultaneously exist until observed (based on the Schrödinger living/dead cat thought experiment), which, on its face, seems to me to belong to theology and not to science. That both...

From here: https://in.answers.yahoo.com/question/index?qid=20100421234931AAnRi1H Please could someone tell me exactly what is causing the repulsion? When it says size of groups, what does it mean? What groups? What's a group? Shouldn't larger things attract, not repel? Is it a structural...

Good Morning / Afternoon, I'm looking at a question which has been given to me and I'm trying to find out what the answer / formula would be to it. The question is as follows: A student has been asked to move a box of mass 15 kg onto a shelf that is at a height 2 m above the ground level and...

The slope of a fitted line = Cov(X,Y)/Var(X). I've seen the derivation of this, and it is pretty straightforward, but I am still having trouble getting an intuitive grasp. The formula is extremely suggestive and it is bothering me that I can't quite see its significance. Perhaps, my mental...

Hi all, I start to read some popular science on quantum physics. The term "entanglement" appears everywhere in quantum communication and other related fields. I am trying to understand this concept based on my undergraduate knowledge on physics. From some online resource, I have a feeling that...

I have read a great deal of psychology and I have a very strong feel that the explanation of human soul must lie in the neurology and study of brain signals especially in strong emotional states like listening to strong lyrical rap music or being in love. I want to discuss it here so we can...

Hi My academic background is in philosophy, and I know very little physics. My attraction to the principle of sufficient reason motivates my question. My understanding of one theory of the origin of the universe is that it started with a "singularity" which then exploded into our universe. It...

Homework Statement Has solution It then goes on to state the solution blows up at , which I understand. My issue is when I do the solution I get (Working)

I had someone ask me how rockets are able to accelerate in space and my initial answer was that the rocket fuel combusts and is heated into an energetic gas, the gas is accelerated out of the back of the rocket (i.e. the rocket exerts a force on the gas), then according to Newton's 3rd law, the...

Isnt "there's no free will" the simplest explanation for "spooky action at a distance" ? Bell himself said it: "There is a way to escape the inference of superluminal speeds and spooky action at a distance. But it involves absolute determinism in the universe, the complete absence of...

I just conducted a lab in which I am testing varying amounts of magnesium to react with a consistent amount of hydrochloric acid, determining which amount of magnesium produces a reaction whose enthalpy is the closest to the theoretical/ideal enthalpy of this equation. I created 3 conditions...

Homework Statement Consider the bivariate vector random variable ##(X,Y)^T## which has the probability density function $$f_{X,Y}(x,y) = \theta xe^{-x(y+\theta)}, \quad x\geq 0, y\geq 0 \; \; \text{and} \; \; \theta > 0.$$ I have shown that the marginal distribution of ##X## is ##f_X(x|\theta)...

hello everyone, i hope you're doing well, i am new to this forum so i am not sure if this is the right place for my question what i am doing is trying to calculate the air flow needed for intake of an RC engine Zenoah G320RC in the attachment files, it's a pdf for the info about the Standard...

Homework Statement I need help with the following problem in C programming language: Define a quiz and add two questions in it with given possible answers. Display the questions one by one and allow the user to choose between 1, 2 or 3 (numbers that represent serial numbers of possible...

So I have a school project that requires me to use a sliding window in order to transmit a file to a server, but I'm having trouble understanding how sliding window works. I don't really understand how rejects are done and how the program knows to send a new packet and then move onto the next...

Hi, can someone please explain how we get 9 independent constants for orthotropic materials in the stiffness/compliance matrix which is reduced from 21 constants of anisotropic materials. A detailed expanation is required and mathematics behind it

I've read some articles online saying that the temperature is a measure of average kinetic energy of molecules so as the temperature increases, more molecules will bump into each other. However, I still don't quite understand why we feel hot when more molecules bump into each other. Is high...

Hello, I am struggling to understand a simple question on limits. I have watched a video trying to explain the theory and even have the answer right in front of me but I still don't understand. Could somebody please explain the steps in detail for me just for the first question as I'm hoping...

Just watched many times (specifically @ 20:13 - 25:04) Ron Garret's 'Google Tech Talk' All was going well - the 2 photon experiment & concept visualised - only that the finality of comprehension wasn't delivered... perhaps because Ron was merely using this for his own purpose. This seems a...

How can we say that when the sun is overhead then its ray will pass through the centre of the Earth , does it happens only at the one place on the earth. How they knew that synene is situated in the middle of north and south

Homework Statement Why do objects that have no external net force acting on them accelerate? Ex. If a ball is on an accelerating train, it will accelerate opposite the direction of the train's acceleration, assuming there is nothing blocking its path of motion and it is not strapped down. My...

why does kinetic energy depend on half the square? if we add up all the velocities does it not produce half a square?

So, I've been viewing this calculator website, and from it i figured out how to do the Lorentz Contraction and Time Dilation formula. However, When i stumbled upon this one... No matter how i tried, I couldn't figure it out. So, Please help. http://keisan.casio.com/exec/system/1224060366

Hi everyone. I would like to ask about this light sensor using not gate circuit. I use LDR as an input and a LED as an output. I have tried this circuit in Proteus, and it works. When the LDR 'off', LED turns on, and vice versa. But i don't really understand about the working principle of this...

Sorry for the title, and sorry if there is already a thread on it. This induction charger for a public transport bus. Can anyone break it down into basic formulas of high school physics. The air gap is frikkin huge. Earlier prototypes apparently had a secondary coil on the bus that was lowered...

I'm not a specialist in this subject, so bear with me. I've always wondered why one claims that the electromagnetic and weak interactions are unified, but the strong one with the (unified) other two is not. Mathematically, I'm aware that the full gauge group of the SM is ## U(1) \times SU(2)...

I am still a bit puzzled by this video: Does this mean that force exerted on an electrically charged particle facilitated by moving through magnetic field B is due to special relativity, and not virtual photons acting as magnetic force carriers? Thanks

https://anhngq.wordpress.com/2013/04/25/the-cauchy-formula-for-repeated-integration/ Could someone please explain, bit by bit, how the formula works? For instance, why are we integrating with respect to sigma, up to sigma in the equation before it?