Nature Definition and 712 Threads

"Fluidic" nature of space itself In the following article "the theory reduces to GR coupled to an incompressible fluid." 'Empty Black Holes, Firewalls, and the Origin of Bekenstein-Hawking Entropy' http://arxiv.org/abs/1212.4176 "But why an incompressible fluid? The reason comes from an...

Homework Statement An electric potential difference accelerates electrons from rest position towards a screen. Just before striking the screen, the electrons have a wavelength of 1.0*10^-11 m Find the electric potential difference.Homework Equations p=h/λ ΔEK=qΔVThe Attempt at a Solution...

Homework Statement An object has a wavelength of 8.4*10^-14 m and a speed of 1.2*10^6 m/s. Find the mass. Homework Equations p=h/λThe Attempt at a Solution p=h/λ mv=h/λ m=h/λv m=(6.63*10^-34)/((1.2*10^5)(8.4*10^-14)) m=6.577380952*10^-26 kg Is this correct? (other than significant digits)

Here is an animation from Wikipedia : http://en.wikipedia.org/wiki/File:Torque_animation.gif The angular momentum is given by the Cross product of r and p We can see that the direction would be perpendicular to the direction of rotation of the particle (as shown in the animation) I don't...

I find it difficult to visualise how the magnetic field generated by a coil can be the same as the field of a permanent magnet. Are the magnetic fields the same or is it just that the effects are the same in that they both attract iron or magnets in the same fashion? Visualising the field...

On the nature of the "infinite" fall toward the EH Observers Alice and Bob are hovering far above the event horizon of a block hole. Alice stops hovering and enters free fall at time T_0. Bob waits an arbitrary amount of time, T_b, before reversing his hover and chasing (under...

While this may seem like a silly question, I had difficulty answering it completely. "If space is a vacuum, why aren't we somewhere else already?" If it is truly empty, devoid of any substance or mechanism whereby it might restrain or compell the action of an entity, what keeps entities...

Would the following explanations suffice to explain why the photoelectric effect shows the particulate nature of light? 1) There is instantaneous emission of photoelectrons when the energy of the photon is greater than the work function of the material. 2) There is no emission of...

Also, if a particle is traveling through a uniform electric field, does anything change as it leaves the field if the electric field strength increases? If you're asked to find the magnitude, is it just the modulus of those values? What is a vector?

Has this ever happened to you? Did you ever feel the need to distance yourself from modern civilization and go back to jungle, beach, rock, desert, snow, plain etc. places forever? So, I was watching a lot of discovery channel, checking out dive fishing videos, reading adventure books. And I...

What prevents helium from becoming solid at normal atmospheric pressure? All other elements are solid at 0K, why does helium stay a superfluid liquid?

Homework Statement Monochromatic light falls on two very narrow slits 0.046 mm apart. Successive fringes on a screen 5.30 m away are 7.0 cm apart near the center of the pattern. Determine the wavelength of the light to two significant figures. Homework Equations x2 ≈ Lθ2 = L (2λ) / d...

is math "real", or created by humans, and other questions about the nature of math. These questions have disturbed me for the past month. If I define a certain mathematical structure, say a function, is it real? what makes it real, when a class of students ponders a function are they all just...

Homework Statement f(x,y) = xy(9x^2 + 3y^2 -16) Find the critical points of the function and their nature (local maximum, local minimum or saddle) Homework Equations The Attempt at a Solution I have partially differentiated the equation into: fx = 27yx^2* + 3y^3 -16y fy =...

A few questions for anyone kind enough to reply and help me understanding this matter: 1. Since electromagnetic waves in vacuum have a maximum speed is this speed limited by the permittivity and permeability of the vacuum? 2. Or is it related to the density of the vacuum as it is for waves...

Citing a recent post from Dr. Chinese, it seems like quantum entanglement experiments are showing something beyond the current standard model. https://www.physicsforums.com/showthread.php?t=637454 If particles can be entangled to other particles that only existed in the past, it seems that it...

As far as I understand, the wires in classical Newtonian mechanics are inextensible, unbreakable and so forth. The part that confuses me is that sometimes there are two tensions in the wire, or rather the tension is in both senses. Is that because there are opposing forces acting on the two...

Homework Statement http://insight.ccsf.edu/file.php/4599/PDF/Exam1-Fall-2011.pdf Homework Equations v^2=T/μ κλ=2∏ ω=2f and many more The Attempt at a Solution Starting with 1a the λ is 4/3*.015cm=.02cm since by the diagram the distance between the labeled point is 3/4 the...

If DM is immune to the electromagnetic force but not to gravity and the universe is homogenius, would we expect the find DM at the centre of normal matter bodies such as stars and planets trying to form black holes?

Homework Statement Find and characterise the stationary points for F(x,y,z) = x2 + xy + y2 - 2z2 +3x -2y +z The Attempt at a Solution I found fx, fy, fz and let them equal to 0. Solving gives me the critical point (-8/3,7/3,14). From here I'm not sure how to determine the nature...

Is the current mainstream thinking that spacetime was created with or by the big bang? I've read many posts about a "wrap-around" universe in which there is no border, and traveling to the "edge" of the universe would pop you out on the other side. I've done some brain-wracking, and I haven't...

Homework Statement The book defines a 1/2 wave odd symmetrical function as each 1/2 cycle is a mirror image of the next. \begin{array}{l} {a_0} = 0 \\ {a_n} = {\textstyle{4 \over T}}\int_0^{{\raise0.5ex\hbox{$\scriptstyle T$} \kern-0.1em/\kern-0.15em \lower0.25ex\hbox{$\scriptstyle...

When two cylindrical magnets are brought close together so that the North pole of one is close to the south pole of the other, there is an attraction force between them. But what is the nature of this force? I used to think that this force is nothing but Lorentz force that the magnetic field...

Hello. Gravity is by far the weakest force in the universe, yet it is the only force with an infinite range. This fact about gravity doesn't make a whole lot of sense to someone like me; someone with little knowledge of Physics. Why doesn't it make sense? It doesn't make sense because...

Forget about the GOD for the moment, we do not need GOD to create the universe (As pointed out by Prof.Stephen Hawking both matter and anti matter ruling out the existence of god) , First there was bang and then all the mass produced (perhaps by higgs boson (waiting for updates from CERN)) Space...

What is an electron made of and, what are other so called fundamental particles made of?

[FONT="Arial"]My Question is, “why the phenomenon of relativity is not progressive in nature”. For example we say that a person moving with ‘c’ faces the time dilation say t. But since the person is still in inertial frame (constant velocity or zero acceleration) and also moving with ‘c’ with...

Question on the "probabilistic" nature of QM I read very recently something that I interpreted as stating that certain quantum-mechanical phenomena are necessarily probability-based: for instance the exact path traversed by a photon/electron in the double-slit experiment. That's all well and...

we are given an equation x5+x=10 . How to prove that the only root for the equation is irrational? I'm an average 12th standard student. So, please keep it low. Thanks in advance.

i read on wikipedia that 2 Cu (s) + H2O (g) + CO2 + O2 → Cu(OH)2 + CuCO3 (s) although doesn't the copper form copper oxide first? and then the copper oxide reacts with water and CO2 to form copper carbonate and copper hydroxide?

Conformal Nature of the Universe (at PI) "Is nothing sacred?" Starting Wedesday 9 May at PI will be an unusual conference at Perimeter. Some topics of talks include: Shape Dynamics (Barbour, Koslowski, Gryb, Gomes...) Relationalism (Edw. Anderson...) Horavaism :smile: 't Hooftism :biggrin...

Hi all, I have a little out of track question and I was forced to consider this after reading FQXI Essay competition title Is Reality Digital or Analogue and Kant's Critique of Pure reason simultaneously. If I am not wrong, according to Kant, there are limits of pure reason. Is not the...

Hi, I didnt see specific relative theory and time mentioned on this site that tries to explain the nature of time: http://www.thisistime.co.uk/7.html I can understand the part of motion and change, which defines time. But the problem is that relative theory of time is used on GPS...

I'm sorry, I just realized I put this in the wrong subsection. While I figure out how to fix that, please have a look anyway. __ Homework Statement Given x \inℝ And s =\frac{4(x^{2}) + 3}{2x-1} Prove that s^{2} -4s - 12 ≥ 0 Homework Equations The discriminant Δ, (in order for which to be...

So if light acts like waves when interacting with huge objects and acts like regular particles when interacting with very small bodies like atoms and electrons.. now I know this might sound silly, but what if the photons were to be in the size of a tennis ball, and the electrons also relatively...

A few years ago I came to this forum to ask about the issue of space expansion...and the answer I got then was that the expansion is the nature of the space (or space-time) according to relativity or some other more advanced theory...no one used dark energy to explain the issue at that...

if the displacement of the body is proportional to square of time. what is the nature of motion of body?. thank you

Hi, I am trying to get a few fundamental concepts sorted out in my mind associated with the maths of non-commutative operators and the physical implications on QM. As such, I am simply looking for confirmation, clarification or corrections to any of the following issues. One of the most...

The wave function represents all that can be known about a quantum system, but that usually means that we only know the energy. In the case of entanglement we know the energy but not the momentum (e.g. angular momentum) of its components. When one component of an entangled system (one spin up...

Inspired by Skyrim: Not sure if this is the right section TBH What is better - to be born good, or to overcome your evil nature through great effort? I personally think it would be the latter because one who is born good cannot not truly understand the essence of evil nature, its...

the nature of mass at rest is different from that in motion due to dual nature,therefore. the brains of the astronauts while in space are expected to work in different way. Is that so ?

I think the experiment of Newton's bucket is wrongly criticized.They deny the absolute velocity,it is right ,but they agnore the absolute nature of motion,which is not relative to other system,but is relative to the thing itself at the previous adjoining instant.Such as the expanding of universe...

Light consist of photons but also has a wave nature which consists of electric and magnetic waves right? So when another particle moves, say electron it also shows wave nature according do debroglie. Will it also have electric and magnetic fields? Or is it just this special photon which has...

Hello, 1a) Generally, would anyone mind discussing what laws of nature (aka. physical laws, physical principles, scientific laws, etc.) are? 1b) Are they only to describe phenomena, i.e., interactions, behaviors, etc.? 1c) Or do any describe why certain entities are similar? Note: by...

"At a distance of 1.5 fermi, the nuclear force becomes maximum and remains attractive in nature. However, at a distance of 0.5 fermi, the nuclear force suddenly becomes repulsive. " Revered Members, Nuclear force is a short range force, so naturally when the distance between the nucleons...

ok, so I am coming from a complete automotive perspective so when i refer to voltage applied to an electric motor (engine starter motor for example) i mean 12v direct current. typically consisting of a battery that puts out 500 cranking amps.. the question is real simple but iv noticed auto...

Are principal strains necessarily tensile/compressive or can they be shear strains also? And are the principal strain planes parallel to principal stress planes at a point?

I didn't get the concept of dual or hybrid nature of nabla? I-e vector differential operator .. Is it means that nabla can produce a vector from scalar field (gradient) and scalar from vector field(divergence) ? What's the concept of Nabla's Dual nature ? Please explain..

Hi all, I am from electronics background, yet I have studied quantum mechanics. Lately I have been reading Prigogine I., "From being to becoming". (If I am correct) the book deals with the one directional nature of time as it flows from past to present and onwards to future. But I did not get...

The world seems to me to be rather arbitrary. I don 't know if people feel the way I do. Scientists apply for government grants to gather data, and conduct experiments. Some scientists look at the data, and write down equations. If those equations are sufficiently fundamental, then some...