Explanation Definition and 961 Threads

Homework Statement Boxes are placed on a slope at uniform intervals of time trelease and slide down the slope with uniform acceleration. Knowing that as a box B is released, the preceding box A has slid 6 meters down the slope and that 1 second later they are 10 meters apart, determine the...

I'm from a country in Africa where I didn't have the privilege of learning the Standard Model, so I'll try and rephrase my question here: https://www.physicsforums.com/threads/why-is-the-electromagnetic-field-not-a-charge-field.857927/#post-5384284 In a way where my ignorance doesn't outrage...

Homework Statement This formula we've been using recently, I don't understand where it comes from. Homework Equations T = 2pi * sqrt(m/k) The Attempt at a Solution Hooke's law: F = -kx E(total) = .5mv^2 + .5kx^2 Circumference of a Circle: C = 2 * pi * r I figure these piece together, but I...

Hi, I can derive a few properties of the limit inferior and limit superior of a sequence of sets but I have trouble in understanding what they actually mean. However, my understand of lim inf and lim sup of a sequence isn't all that bad. Is there a way to understand them intuitively (something...

It's quite chilling that gravitational wave has been detected.. can force based explanation of gravity waves still be possible? How? or does it prove 100% that GR is true or gravity is really spacetime curvature?

So understand how to solve a problem using the equation: ΔS=Q/T But is there a conceptual explanation for why the equation works. And I'm not looking for a proof, but I simply want to understand why this equation should be intuitive. Thanks for your time!

How these are working: Is current flowing? In the first case I don't think so. In the other... the wire is insulated like in a coil I think and then no current also. But why need the battery and why the battery is discharging? Can current flow through a magnet without demagnetize it? What...

let's look at force at the atomic level to understand the Newtons third law of motion. I'll use Helium atoms as an example. Now imagine we start with one atom HE2 stationary, and throw another atom HE1 at it.It is the velocity of HE1 that affects the motion of HE2 , because the system of these...

Homework Statement Given the following reaction that has reached equilibrium: NaCl(s)←→NaCl(aq). For the phase equilibrium to exist, the NaCl(aq) must be a solution that is A. concentrated B. saturated C. dilute D. heated E. unsaturated Homework Equations - The Attempt at a Solution I chose...

Been lurking on these threads looking for easy explanations of E=mc2 as it relates to nuclear fission weapons. Shame, SHAME, to yall advanced physicists who dismiss and disrespect and flame amateurs on other threads asking for easy examples for kids. I'm a humanities teacher teaching...

When I first heard about the OPERA apparent superluminal results on the measurement of neutrinos speed, I tried to locate an explanation using all the possible relativistic effects. All were too small to account for a difference of 18 meters of virtual distance among photons and neutrinos. Then...

I am using Spivak calculus. Now Iam in the chapter limits. In pages 97-98, he has given the example of Thomaes function. What he intends to do is prove that the limit exists. He goes on to define the thomae's function as f(x)=1/q, if x is rational in interval 0<x<1 here x is of the form p/q...

Does a valid experimentally verified scientific explanation exists for the phenomena of quantum entanglement? Doesn't Quantum correlations demand explanations? What is the explanation for Quantum correlations? Is it, 1. Retro-causation 2. FTL 3. Information is finite and far more fundamental...

The following assessment of a Bell experiment is based on N. David Mermin's example and is intended for persons with very little understanding of mathematics and physics (myself included). Assumptions (A1) A source emits a pair of particles with some opposite pieces of information. (A2) The...

A bicycle powered generator uses mechanical energy to create electrical energy, yes? I pedal, and some form of coils and magnets move around and around and generate electricity. This I understand. Upon pedaling at "x" rpm's, I'll produce a certain amount of watts of electricity, correct? If...

One of the most accurate formulas for dispersion is the Sellmeier equation: n^2(\lambda) = 1 + \sum_i \frac{B_i \lambda^2}{\lambda^2 - C_i} Dispersion does not arise with Huygen's Principle. Is there a theoretical model that describes dispersion and explains why Sellmeier's equation takes the...

I would like to understand basic construction of entanglement "explanation" in QED. As I understand because we talk about coincidences QED explanation necessarily involves Fock states. And Fock states are expressed using annihilation and creation operators, right?

I have seen a video in which the time dilation due to velocity is explained by saying that light and light interactions inside a moving body must travel a longer distance in space, which reduces the passage of time. Video: This explanation is new to me, and in fact, I recently heard an almost...

So its been a while since I studied maxwells equations, anyway: So From my ignorant perspective, trying to derive conceptual meaning from these, I can see that the time dependant study there is some conductivity x the partial differential of the magnetic vector potential plus the cross product...

Wikipedia states that: "If the measurement is close enough to the surface, light rays can curve downward at a rate equal to the mean curvature of the Earth's surface. In this case, the two effects of assumed curvature and refraction could cancel each other out and the Earth will appear flat in...

Why can't distortions in spacetime be used to describe the fundamental forces other than gravity, i.e. the electromagnetic force, the strong nuclear force, and the weak force?

Homework Statement I was to calculate the Fermi Wave Vector $K_F$ for a metallic structure then explain why the nearly free elctron model is consistent with its behaviour?The Attempt at a Solution After calculating the wave vector, I see that the fermi wave vector is within an energy band...

I understand that there is no electric field inside a charged conductor, but; I don't understand why a connection to ground made on the inner surface of said sphere will flow current. Is this not correct?

Hello, I am unsure as to why the probability of A U B = P(A) + P(B) for sets A and B being disjoint. Why do we add the two probabilities? Is it because the sample space remains the same but now we add the numerators as the number of events have increased and that is why we are adding the two...

Imagine two observers, one accelerating and one inertial. The accelerating observer detects a thermal bath whereas the inertial observer detects a vacuum. I would imagine that this hot gas would thermalize the accelerating observers spaceship, but how does the inertial observer reconcile this...

I have decided to self-teach myself A-Level Physics. I am confused about one particular step of a solution to a certain problem that the textbook provided. Problem: A stone is thrown vertically upwards at ##15 ms^{-1}##. How long is the stone in the air until hitting the ground? There are a...

Muons time dilation from the Earth's frame (and length contraction of Earth's atmosphere from muon's frame) is the usual explanation of the fact that muons reach the Earth when they shouldn't just by their rest half-life. My question is if the explanation based on differential aging(different...

F(x)=5/(x^2)-9 Find F'(x)&F''(x) Find the Vertical Asymptote, Horizontal, and Slant

Hi all, I encounter an un-explainable question during my lab, so I figured it would be a good shot asking here. Also, my English isn't perfect, so if there is anything unclear, say it out and I'm happy to clarify it. In the lab, we placed a sled on a track and slowly lifted one end of the track...

Suppose that a static electric field E is applied on a conductive crystal. Then, how quantum mechanics describes the electron movements in the crystal? I have been trying to find an explanation, but have not found any. As I understand it, we could treat the E field as a time-dependent...

Hi all -- can anyone offer a qualitative explanation of why it is that couplings run with the energy in *relativistic* quantum theory, and not in non-relativistic? Some insight here would be much appreciated. Thanks.

Homework Statement I don't undersand why Pr(A l B) = P(AnB)/P(B) Homework Equations conditional probability[/B] Pr(A l B) = P(AnB)/P(B) A given B The Attempt at a Solution I can make a bunch of problems with this definition intuitively, but I really want to understand with sets what is...

i need help with finding the domain for a function where there is a square root , here is the picture of such questions : http://imgur.com/YcqadOe please see the picture, there are two questions in it, 35 and 37 let's start with question 35, this is how i try to solve it : x^2 - 5x > 0 x...

Homework Statement The Tensions in four cables are equal: |T1| = |T2| = |T3| = |T4| = T Determine the value of T so that the four cables exert a totl force of 12,500-lb magnitude on the support. (Inser a picture of 4 connected cables angled 9, 29, 40, 51 degrees respectively) My question...

My Physics teacher told us to use a = g x sinθ during a lab trying to find how close we could calculate gravity using an inclined plane, a moving cart and a motion sensor to measure acceleration. He also drew a diagram next to the formula. I just wanted to confirm that his diagram was wrong, or...

Why is it that the electric field at Z due to Q1 and Q3 have their horizontal components cancel and also why is the resultant for E1+E3 result in the negative z directiom?

Hi, my high school astronomy class designs/builds antennas to detect VLF radio for solar flare detection. Recently, and regardless of their design, we get a strange "mirrored" shape to the dB vs frequency plot. The shape of the graph before roughly mid-band is exactly mirrored about the...

We started Network analysis and we were given Circuit Diagrams to be reduced using the following: Kirchoff's Laws i.e KVL and KCL Source Transformation Superposition Theorem Thevenin's Theorem Norton's Theorem and Star-Delta Conversion However I wasn't given proofs for any of these theorem...

Veritasium made a video on how a flight wheel seemed weightless when spinning: He then explained in a following video that the reason why it felt weightless is because while he lifted it, he was also swinging the wheel in the x-y plain, which, combined with the wheel's own rotation around the...

Hi, I read several approach to the explanation of aerodynamic lift. Bernoulli, Newton, Kutta-Joukowski. I found a topic about discussing Bernoulli and Newton, and the conclusion was that they are both valid individually. But what about the Kuttaa-Joukowski theorem? And are these approaches all...

A classic topic, however I am new to the physics realm and i would like some help into understanding it. I have just finished reading "An Elegant Universe" by Brian Greene "Six Easy Pieces" by Richard Feynman "A History Of Nearly Everything" by Bill Bryson. And across these books i could not...

Hi, This is not coursework, just private study. Ok, I understand that q is a quadratic residue MOD n if x^2 = q MOD n What I don't understand is how to figure this out? I read a paper that states "8 is a quadratic residue mod 17, since 5^2 = 8 MOD 17", fair enough. It then goes on to state...

Sincé I am not a physicist, but study a lot of quantum physics of my own, I hope you excuse my incomplete knowledge. I have been thinking about the following: If a picture of a simultaneous wave-particle was taken, doesn´t that contradict the fact that waves actually don´t exist, they are...

Hi! I am new to ANSYS and I am trying to understand a simulation done by some one else. I have a disk with a spiral in it, and it looks like there is a remote force being applied at the centre of the disk, but spread over the entire face. I don't understand how this force is being spread...

Mods: I am not sure if this is a Physics question or more appropriate for Cosmology. I read a short discussion (on another forum) about the Boltzmann Brain paradox. I did a little further reading on the web but most explanations were a bit too deep (read: over my head). I wonder if someone...

Homework Statement It's a long winded problem, I'll post a picture and an imgur link Imgur link: http://i.imgur.com/5wvbqO2.jpg Homework Equations Divergence Theorem \iint\limits_S \vec{F}\cdot d\vec{S} = \iiint\limits_E \nabla \cdot \vec{F} \ dV The Attempt at a Solution I'll follow...

nuf said :wink:

Skip to 29:50. Here Feynman is explaining how some laws are not independent of energy conservation. In this case he goes on to explain how instead of using the law of levers were can use energy conservation to see what weight an object needs to on one side be to balance (or be in a state where...

Hello guys. I need an easy explanation regarding Laplace Transform and Fourier Transform. I know it is quite a mathematics question but I need an explanation in which it has something to do with engineering. I already search a bit about them but still cannot find and explanation that easy enough...

Hello! (Wave) I am trying to understand the proof that the expected running time of quick-sort is $O(n \log n)$. Could you maybe explain it to me?