Questions tagged [scales]
The scales tag has no usage guidance.
89 questions
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Which way does the scale tip?
I found the problem described in the attached picture on the internet. In the comment sections there were two opposing solutions. So it made me wonder which of those would be the actual solution.
So ...
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Are all machines linearly scalable?
For all machines (cars, elevators, computers, etc), when size, power requirements, dimensions are scaled by a constant N, will it work just as is?
Will a car with all its parts 10x larger still work ...
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What does the Reynolds Number of a flow represent physically?
What does the Reynolds Number of a flow represent physically?
I am having trouble understanding the meaning and the utility of the Reynolds number for a certain flow, could someone please tell me how ...
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What is the hierarchy problem?
BACKGROUND
So far I understood that the hierarchy problem was the large difference between the gravitational scale, $M_{pl}\sim 10^{18}\; [GeV]$, compared with the electroweak scale, $M_{ew}\sim 10^3\...
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Does the scale at which the observations are made, have a role in the physical laws which are obtained? [closed]
I am starting studying quantum mechanics and observed that classical physics ceases to be accurate at the microscopic world (atomic length-scales).
Here is my question, cast as a thought experiment ...
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Planck mass is about the mass of one eyebrow hair
Unlike most Planck units named after "Planck" such as Planck length, Planck temperature, etc, the Planck mass seems more closed to daily life. It is about $10^{-5}$g, same order of magnitude of one ...
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What is the logic behind the Fahrenheit scale?
The Fahrenheit scale is defined by fixed points on the scale. What interests me is the apparent arbitrary chosen numbers in these fix-points.
First wikipedia wites from 32 to 212. -and later in the ...
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Why is the string length around the Planck length?
In string theory, it is assumed that a string is about the size of a Planck length, $$\ell_{string} \sim \ell_{Pl} \simeq 10^{-35}\,\text m.$$ Why that length? Why not for example a hundred times ...
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How does such strange microscopic behavior at the atomic level (quantum mechanics) lead to the macroscopic behavior at our level?
So, I'm only a high school student researching quantum physics, and I find it very interesting. However, there's one question that keeps nagging at me in the back of my head. How exactly do odd ...
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Relationship between hierarchy problem and higgs fine tuning?
I often hear of hierarchy problem being used synonymous with Higgs fine tuning (esp with regards with motivations for SUSY). What exactly is the relationship between the two problems? As I understand ...
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How can there be a quantum field theory that predicts all particle masses?
Say I have a theory with only one (energy) scale, e.g. one given by the fundamental constants
$$\epsilon=\sqrt{\dfrac{\hbar c^5}{G}}.$$
In this case, where I can't compare to something else, is there ...
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How can we determine the energy scale of a physics theory?
It is very common in physics, when we refer to the most diverse theories, on the most diverse length scales, we also refer to their energy scale. It is through the energy scale that we classify a ...
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How unique is the length scale picked out by intelligent life? [closed]
Our human bodies pick out a length scale (let’s say 1m). How unique is this scale and why did it arise?
In other words, how much smaller could humans, or multicellular lifeforms in general, be while ...
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If the electron is point like, then what is the significance of the classical radius of the electron?
What is the physical meaning/significance of the classical radius of the electron if we know from experiments that the electron is point like?
Is there similarly a classical radius of the photon? The ...
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Scale invariance at phase transitions
The Wikipedia entry for scale invariance states
In statistical mechanics, scale invariance is a feature of phase
transitions. The key observation is that near a phase transition or
critical ...
- 1,294
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Definition of Fine-Tuning
I've looked in and out the forum, and found no precise definition of the meaning of fine-tuning in physics.
QUESTION
Is it possible to give a precise definition of fine-tuning?
Of course, I guess ...
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Dressing vs. renormalization
In the past, my understanding was always that the processes of
dressing a bare quantity (such as mass or charge) and
renormalizing these same properties
are different things. Dressing, as far as I ...
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Maximum reading after dropping a mass onto a scale
If one drops an object onto a scale, the needle will temporarily spike to a high reading.
Given a mass $m$ dropped from a height $h$ above a spring scale, is there a good way to approximate what the ...
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Why is the apparent weight smaller when you crouch down on a scale?
I am having a problem understanding the concept of the apparent weight change when you crouch down, stand up, and jump on the scale. What is happening that makes the scale change?
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Power law behaviour at phase transition point & presence of fluctuations of all length scales
In physics, exponentials such as $\exp(-r/\xi) $ typically come with a natural length scale $\xi$ while power laws such as $\sim 1/r^n$ don't have a definite length scale (at least not readily ...
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What is a "scale length", and how do I calculate it for galaxies?
I'm trying to work through, understand, and apply concepts regarding mass models of galaxies. Looking at the Hernquist model, I'm finding the equation $$Φ(r)=−\frac{GM}{r+a},$$ where a is the scale ...
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Is there scale by size of all discovered particles?
Atom:
Neutron:
Elementary particles:
Is there scale by size of all discovered particles?
From neutron and proton to electron and to boson?
Compare to each other, like this
I have found many ...
5
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Is there any guarantee that there will be only one point on the isotherm curve of a system that has a certain Y coord?
When reading this part of the "heat and thermodynamics" book of Zemansky,
is there any guarantee that there will be only ONE intersection of the $Y=Y_1$ and the isotherm line?
The alternative of ...
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If Earth was the size of an orange, what consistency would it be? [closed]
I understand that the Earth is composed of a thin crust "floating" over a semi-solid layer of mantle.
I was wondering how it would feel at a human scale, say the size of an orange in your hand. Could ...
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Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?
Suppose we view fluids classically, i.e., as a collection of molecules (with some finite size) interacting via e&m and gravitational forces. Presumably we model fluids as continuous objects that ...
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Why do we have a TeV scale?
When model building we don't want to introduce any new scales into our theory. We usually try to have new particles at the Higgs (TeV) scale (to solve the hierarchy problem), at the GUT scale, or at ...
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For how long must a molecule remain stable to be considered "stable"?
In the Star Trek: Voyager episode The Omega Directive, Seven of Nine says that the Borg synthesized a molecule which was "kept [] stable for one trillionth of a nanosecond before it destabilized". ...
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Is the form of the Lagrangian relevant before the renormalization procedure?
In the renormalization procedure, is writing things like
$$\varphi=\sqrt{Z_{\varphi}}\ \varphi_R\ ,\ \ m_0^2=Z_m\ m_R^2\ ,\ \ g_0=Z_g \mu^{\epsilon}\ g_R$$
and
$$Z_i=1+\sum_{\nu=1}^\infty C_i^{(\...
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If there were no space between nuclei, how big would the Earth be?
I have some people telling me it would be the size of baseball. I am quite doubtful on this. If this is true, then the gaps must be so incredibly huge that everything should be transparent. I am not a ...
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Why is the Kelvin scale formed using the triple point of water rather than the freezing point?
I am trying to learn some thermodynamics by watching the lecture series on YouTube by MIT.
In the second lecture, from 9:00 to 9:45, the lecturer talks about why the freezing point of water as defined ...
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What does Earth feel like when squeezed?
he average density is about 4g/cm^3 so if the earth was in the size of an orange, it would feel like a rather heavy ball.
The crust is relatively thin, and the earth is said to be solid land masses ...
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Is there a relation between large-scale oscillations and small-scale oscillations?
From Neural oscillation - Wikipedia:
Oscillatory activity in the brain is widely observed at different levels of organization and is thought to play a key role in processing neural information.
In ...
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A problem of approximation [duplicate]
Possible Duplicate:
Why are continuum fluid mechanics accurate when constituents are discrete objects of finite size?
When we apply differentiation on charge being conducted with respect to time,...
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What is the Planck scale magnetic field strength?
Using the constants $\mu_0$ (or $\varepsilon_0$), $c$, $\hbar$, $e$ and $G$, it is possible to define two quantities with units of magnetic field :
\begin{align}
B_1 &= \sqrt{\frac{\mu_0 c^7}{\...
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Is renormalization associated with a volume scale or with an energy-momentum and length scale?
Given that real-space renormalization blocks together small volume elements to construct larger volume elements, is it more appropriate/helpful to consider the renormalization scale to be a volume ...
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Why are high energies equivalent to short distances?
Why are the regimes in high-energy collisions called short distances?
Qualitatively I only know that the higher the given energy of the colliding particles "the smaller are the pieces yielded by ...
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Why are log scales so common?
I am currently reading a very nice book on scales in physics. There is a discussion on the different physical scales which are based on the effect of the corresponding phenomena, the given examples ...
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How can a beam balance measure mass?
In Newtonian physics, mass is the amount of matter in an object. So, how can a beam balance measure the amount of matter in an object (which is the mass of the object).
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Weighing machine, kg vs. N
When I stand on a weighing machine and it shows me the number 75 , is it my mass in Kg or the Normal Force due to gravity in N
user232243
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About the formula of the Taylor microscale
I am running simulations of a non-isotropic turbulent flow and I need to compute the Taylor microscale. The formula one can find in the book Turbulent flows (Stephen B. Pope) is :
$\lambda = \sqrt{10} ...
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Bath-Scales weight or mass?
I read that bath scales measure body weight and not mass which means they measure m*g and not m.
If I got a reading of 50 kg, does that mean that my mass is nearly 5?
Units of m*g aren't kg so why ...
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What would a regular bathroom scale indicate as it's sinking underwater
It seems intuitive that a (waterproofed) spring-based scale placed at the bottom of a lake would indicate the weight of the water column above it.
But assume the scale sinks from the surface of the ...
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Formula to get scales of the two components (radial and perpendicular) of Baryonic Acoustic Oscillations (BAO)
In an astrophysics context about BAO (Baryonic Acoustic Oscillation), it is written on the following paper BAO paper :
"BAO are much smaller in amplitude than the CMB acoustic peaks, and are ...
user87745
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sensitive scale & resistance of analog current meter
Does the resistance of an analog current meter increase or decrease when it is set to a more sensitive scale (lower range)?
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"Kilogram" confusion: If you weigh a stationary object in "kilograms" and divide the result by about $9.8$, does that tell you the mass of the object?
Update: I appreciate all of the answers very much
In a way, I'm delighted to find that such a simple question has generated so much disagreement (most of which can be attributed to issues with wording,...
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Why is current not 0 in a regular resistor - battery circuit immediately after you closed a circuit?
In regular open circuits with either a capacitor or inductor element, (when capacitor is uncharged) with a battery, when a switch is closed to complete the circuit the current is said to be 0 because ...
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Where is the line between Quantum and Relativity?
Its often said QM is for the very small and GR for the very large. This brings to mind that there should be some limit at which one starts to apply and the other stops. Now I know there are more ...
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Energy scales and Lorentz Transformations
There are many particle physics processes where the initial particles must have some minimum energy in order to create the final ones. However, since I could just run through the lab really fast in ...
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Explanation of energy levels in molecules, atoms, nuclei and their relationship
Why are the energy levels of molecules, the atoms that form them and the nuclei inside the atoms considered separately? Or phrased in a different way- what is it that makes their energy levels so ...
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Energy density at a given scale in terms of the Energy Spectrum
Background:
Let us have a turbulent fluid with a random velocity field $\mathbf{u}(\mathbf{x})$.
The volume averaged kinetic energy density $\mathscr{E}_K$ can be expressed as
$$\mathscr{E}_K=\frac{1}{...
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