Explanation Definition and 961 Threads

Can anyone explain how the time dilation formula works? T=t/(√(1-v^2)/c^2))... ... What does the 1 stand for? Why include it? Can you write down the process of the formula?... How does ((C*t)^2))/c^2-v^2 lead to the time dilation formula? Please explain the process.

The reason why there is far more matter than anti-matter in our universe is because we are going forward in time. But if we reverse the direction of time anti-matter will become more prominent and I believe that at singularity there is a balance between both of them. The interaction between them...

1. Mendelian experiments only explain dominant vs recessive gene ratios after generations created by assorted types of mating. But how can I explain the puppy's bicolor coat of black and white given that its parents are one black and one white 2. Supposing that W and B are dominant genes...

Here is a new video, addressing a common question on this forum: https://www.youtube.com/watch?v=jlTVIMOix3I It's similar to that one, but has nice narration, and also shows an object thrown upward.

[SIZE="4"]Definition/Summary Torque is the moment of a force about a point. Torque is a vector (strictly, a pseudovector, like angular momentum and any other moment of a vector), and is measured in units of Newton metres (N m or N.m). By comparison, energy is a scalar, and is measured in...

[SIZE="4"]Definition/Summary Heat is the non-mechanical exchange of internal energy, U, between a system and its surroundings as a result of a difference in temperature. By contrast, work, W, is the mechanical exchange of energy as a result of force applied across a moving surface (such as...

I'm stuck on some high school physics, Gauss law... 1. It says this: The electric field outside the sphere is equal as if the charge of the sphere was in it's center. I don't understand this, why is this true? I get it - experiments have showed that and that's how you calculate it; but what's...

Since dark energy and other models for explaining accelerating universe (which is quite hard to explain) are somewhat speculative, I hope that PhysicsForums rules allow some speculation on this subject. I try to keep this short. And this is also a question. Is there any serious research where...

I have been looking into broadening mechanisms and I'm stuck at trying to provide a physical explanation for power broadening. I get how the math shows that at high intenseties the decay rate goes through the roof due to saturation, but how does this increased decay rate manifest in a spread of...

Joe Silk is one of the co-authors. One expects large voids in the distribution of galaxies because of the cobwebby way dark and ordinary matter have condensed. A large void comparatively close by (within a few billion LY of us) could cool ancient background light passing thru on its way to us...

So I'm looking at some technical drawings here (mechanical engineering co-op) and the live load rating is 100 pounds per square foot (PSF) for this particular drawing. My question is this: why is it so low? Just me standing with my feet together exerts roughly 230 pounds per square foot (i'm...

Could anyone give a really quick explanation for gauge theory to me? Or a link, or a book is perfectly fine. I just completely don't understand SU symmetry breaking and etc. etc. I also have a question, is everyone who lurks around here a college professor on quantum physics or something...

Hi, What would be a plausible explanation for the induced supernova of a star? (Or at least an explanation that had a shot at being plausible!) What about a large antimatter explosion in the star's core, perhaps deposited there through a small wormhole? Or could some kind of missile be...

I've done some calculations. At first glimpse, yes it sounds very nice, that with missiles you can attack way outside laser range... On the other hand, based on molar heat and weight of titanium, it looks like to me, that actually melting down a kg projectile only requires a few MJ... while...

Why does the farside of the Moon have a thick crust with a landscape dominated by lunar highlands while the nearside has a much thinner crust with a landscape dominated by maria? This is what the authors of a paper recently published on the arxiv (and accepted for publication in the...

What actually are photons, means are they packets of energy or some sort of matter.

Homework Statement "see attachment" Homework Equations PV=NkbT Change in entropy = Boltzmann Constant x In(Macrostate) The Attempt at a Solution for part A, I knew that PV=NKbT giving that pressure is 101300Pa volume is 1*10^-3 m^3, Kb is 1.38*10^-23 and T=300K I find N to...

Can someone explain what the PID robust methodology is all about in simple words?http://www.irt.rwth-aachen.de/en/fuer-studierende/downloads/pidrobust/ One of the advantages of the method stated is that "capability to process plants with delay time ". Whats so great about that? Usual...

Dear Forum I'm an experimental photographer. During the last two years I've been developing a technique which I call light plane photography (LPP). LPP is a photographic technique that uses a plane of light and a camera to record photographs with unique optical effects. Here's three...

I've visited a great many sites and looked at papers to fully understand this, and still have some confusion regarding the Hanbury Brown and Twiss effect. Classically, speaking, we treat photons as waves. the math yields a correlation function which boils down to a constant term and a cos...

Is this a valid explanation of why adding heat also adds mass? The closer to the speed of light something is going the more force it takes to increase it's acceleration in that direction. If you have two objects of uniform composition and if the only difference between the two is that one...

Explanation of questions for first problem: We are three brothers(X, Y, & Z) and three sisters(A(45 years), B(42years), & C(24years)). Our neighbor are three brothers(K(45 years), L(35years), M(32years)) and five sisters. My three sisters are mentally ill. A became mentally ill when...

Homework Statement -4x1 +2x2 =2 4x1 -3x2 -2x3 =-3 2x1 -x2 +(k - k2)x3 =-k Find the values of k for which the system has 1) unique solution, 2) infinitely many solution and 3) no solution The Attempt at a Solution In REF: the matrix is -4 2 0 | 2 0 -1 -2 | -1 0 0 k(1-k)...

College sophomore here and just wanted to ask for an explanation of terms that I have come across in my math and philosophy courses thus far, but without direct teaching of them. I've seen these terms used in forum discussions and mentioned off-handedly by profs., but don't have a specific...

Hi, I'd really like to understand How a torsion balance works and exactly how You can use math to derive the Coulombs law. Is thre a good - realtively easy to understand - video or do someone have some good notes explaining exactly how it works? I'd really appreicate it.

Hello, I am looking for some clarity on the second law of thermodynamics. I am an amateur physics student and only just beginning and so my understanding is currently very basic! I have watched Brian Cox's Wonders of the Universe, where he talks about the second law of thermodynamics being...

Homework Statement Find the result of mixing 10g of ice at -10 deg celcius. Specific heat capacity of ice = 2.1 J/g K. Specific heat capacity of water is 4.2 J/g K. Specific latent heat of ice = 336 J/g. Homework Equations The Attempt at a Solution 0.625g, temperature will...

I am not proposing a particular explanation and just in case you suspect I have something in mind, I must tell you that I don't. I was wondering if anybody here has some ideas. I understand that you may have objections to my question. One of them might be that a mechanistic model would not work...

I am doing a problem on the "super symmetric harmonic oscillator" Defined by.. \hat{H}=\hat{H}_b+\hat{H}_f= \hbar \omega \left( \hat{b}^{\dagger}\hat{b}+\hat{f}^{\dagger}\hat{f} \right) I am given the operator.. \hat{Q}=\sqrt{\hbar \omega} \hat{b}^{\dagger} \hat{f} and asked to show...

It's been a while since I've dealt with sequences and series. Here is my explanation of sequences and series and let me know if I am right or wrong. A sequence is just a list of numbers. By convention, we use the letter ##a## for sequences and they are written in a form like so...

Homework Statement Homework Equations After looking through this on Wiki, I'm a little confused as to how these partial fractions are multiplied out. Is there a rule or something for this? With simpler partials I can do it but this one is something else! The Attempt at a Solution

Homework Statement Could some one help me understand capillary Force?Homework Equations The Attempt at a Solution If we use a capillary tube sticking in a water cup as an example. The phenomenon will be water level is higher in the capillary tube than that in the water cup. I understand that...

Hi everyone, Can someone please explain to me what happens here? Why does the polarity reverse? My friend explains it like this, I quote: "as opposed to what is taught in schools, magnets have a centralized force field". Is there something to this? What happens here...

Homework Statement Explain qualitatively how it is possible for the projectiles to have the same range despite having different launch angles Homework Equations x = voxt The Attempt at a Solution A projectile's range is determined by its x component of the initial velocity and the...

Homework Statement a) f(x,y)=√ [1−(x2+y2)] b) f(x,y)=2cos(4x+y2) The Attempt at a Solution a) The domain is such that x2 + y2 must not be greater than 1 In other words, this is expressed (as stated as an option on the answer sheet) as "xy-plane without the line x=y" Why is this...

1. Homework Statement [/b] Suppose the lim(x,y) →(0,0) (xy)/SQRT[x^2 + y^2] if it exists find the limit. The Attempt at a Solution x = rcosΘ y = r sinΘ r = SQRT[x^2 + y^2] ∴ lim[SUB]r → 0 (r2cosΘrsinΘ)/ r = rcosΘsinΘ \leq r and so -r \leq(xy)/SQRT[x^2 + y^2] \leq r ... ... I can...

Homework Statement I've tested the circuit above, when the switch is in the 2nd position (not the one on the picture) and got the below graph from the plotted data I received. The capacitor C1 has been charged to 4V, and will start to discharge through R3. I'll have to explain...

How can a magnet be explained based on quantum properties? This seems like an obvious thing, but I can't find it online. The best I can do on my own is that systems are at lower energy when the spins are aligned, so that's why magnets attract one another. The spin transfers angular...

I have read some fairly vague descriptions of charge that say it can be looked at as the amplitude for a particle to exchange a photon. For example, when two electrons repel, it is because a photon is emitted from one too the other, which would change the direction of both equally and...

Can anyone explain very clearly(to a n00b like me) right ascension and declination and how to navigate to stars using this system?

I'd like to figure out why f(x) = x^n - r e^{i \theta} = \prod_{j = 0}^{n - 1} ( x - r^{1/n} e^{i \theta / n} e^{2 \pi i j / n} ) , as I've seen it used as an identity in a few courses but I cannot figure it out. Could somebody shed some light? I understand they are the roots of the function...

I have a disagreement with a Quantum mechanical scientist about a double slit experiment with polarizers, which gives interference or not depending on "which path" knowledge of the photon. That is alright with me, but I can calculate the same results with classical wave formula. He does not...

Homework Statement Hello, A dipole moment is placed in a uniform electric field oriented along an unknown direction. The maximum torque applied to the dipole is equal to 0.1 N.m. When the dipole reaches equilibrium its potential energy is equal to -0.2 J. What was the initial angle between the...

Hello. This is part of a solution but I don't understand the underlined part. Why is it equals to 0?

I have been looking at the difference and I know one is power and one is energy. I understand that a 2kW kettle on for an hour uses 2kWh but on for 30 minutes uses 1kWh. But with power generation it seems this is constant. If a plant puts out 100kW it does this all day every day regardless of...

Hi everyone, today I had a thought coming across my mind when I woke up, and I think it might be an explanation for the particle-wave duality. Now, when we are talking about a particle, one thing that has to be mentioned is the uncertainty principle. If you divide space into equal volumes for...

Apologies if this has been discussed in other threads already. I did a quick search on 'chain fountain' and got no hits. If you coil a length of chain into a container and let it slip out over the lip under its own weight, it will start to form an arc through the air, without touching the lip...

Electric field of an electromagnetic wave incident on a metal accelerates free electrons, and these accelerating electrons then emit radiation opposite to the electric field of the wave, thus reducing the resultant amplitude in the forward direction. Radiation emitted in the backward direction...

Hi, I understand that the PWM inverter drive system first uses a diode bridge rectifier in order to convert the AC incoming into DC before using an inverter to convert this DC into PWM for use on the induction motor. Could someone please explain in simple terms how the PWM inverter section...

hello, i have a question about an explanation of integration as finding the area under a curve. I don't have any problems doing the integration but it's more a case of why? Finding the area bound by two curves is easy enough but what does that area actually mean? I know that it's a...