Questions tagged [scales]
91 questions
86
votes
7 answers
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 basically the question would be the following.…
Peter Raeves
- 973
31
votes
1 answer
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 like a normal car, just larger?
Zaenille
- 863
11
votes
2 answers
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 this type of dimensionless factor is significant…
user27182
- 1,667
10
votes
2 answers
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, $M_{ew}\sim 10^3\;[GeV]$.
However, I heard that the hierarchy…
Dox
- 1,778
10
votes
5 answers
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 eyebrow hair or a flea egg.
I am just wondering is…
Yingfei Gu
- 1,032
10
votes
2 answers
Does the scale at which the observations are made, have a role in the physical laws which are obtained?
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 regarding the change of the scales:
Imagine an…
Socre
- 547
9
votes
3 answers
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 History part we have from 0 to 32 to 96(based on a…
hpekristiansen
- 1,460
9
votes
1 answer
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 it, the quadratic divergence from the Higgs self…
user788171
- 977
9
votes
2 answers
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 larger?
Asmund
- 91
- 1
- 2
9
votes
7 answers
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 behaviors like quantum parallelism that occur on the…
Brandon
- 193
8
votes
4 answers
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 a way to argue…
Nikolaj-K
- 8,873
7
votes
3 answers
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 theory as being classical, quantum, or relativistic,…
lucenalex
- 387
7
votes
3 answers
How unique is the length scale picked out by intelligent life?
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 sticking with approximately the same architecture…
Michael Angelo
- 718
6
votes
2 answers
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 most of us understand the empirical meaning of the…
Dox
- 1,778
6
votes
3 answers
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 had come to learn, was the result of switching on…
Janosh
- 1,294