Questions tagged [estimation]

A rough calculation or an approximation of the value, number, quantity, or extent of something so that it is usable for some purpose even if the input data may be incomplete or uncertain.

Filter by
Sorted by
Tagged with
2 votes
0 answers
30 views

How could we estimate the number of molecules below which a fluid cannot be adequately modeled by the Navier-Stokes equations?

As is known, the Navier-Stokes equations are an approximation in the continuum mechanics to model an aggregate of independent molecules, which, although they can move freely, interact strongly with ...
user avatar
  • 345
1 vote
1 answer
75 views

Could we be sucked up entirely by a micro black hole?

The hot question about being ripped apart in a black hole (no one can deny physics is boring!) got me thinking. If you cross the event horizon of a supermassive bkack hole, nothing noticeable will ...
user avatar
  • 1,651
15 votes
9 answers
9k views

Can a balloon start from Earth and fly to the Moon, using Helium for lift to the top of the atmosphere and then as propellant?

The JP Aerospace's Tandem airship achieved a record-breaking 28,982 meters for the highest airship flight. After reaching this height, can the helium balloon be used as a propellant, the same way if ...
user avatar
  • 1,855
0 votes
1 answer
41 views

Is there a way to calculate the blast radius of an explosion starting with the yield of the bomb? [closed]

I am working on a video game with missile-oriented combat, and I would like to input a yield for a missile instead of directly giving it a blast radius, and have the program calculate the blast radius ...
user avatar
1 vote
1 answer
56 views

What is the largest hollow structure that could be made before gravity becomes a problem?

Assume realistic strength of materials, like that of steel or stone, or even something with "good" properties like carbon fiber, or advanced ceramics. If one was to put together a hollow ...
user avatar
  • 254
0 votes
2 answers
89 views

Taking into account the Pauli Exclusion Principle, how many particles can you cram into a really small space?

I'm trying to understand the basic concept of the Pauli Exclusion Principle, but my former question here did not provide an answer. So let me rephrase it. One way of describing the PEP is that you ...
user avatar
  • 3,486
0 votes
0 answers
14 views

Translating Parameter Estimation Principles of Quantum Weak Measurement to a Classical Problem

I am not an expert in quantum theory. I want to carry out some parameter estimation on a set of data I have. I have a model for the data with the parameter(s) of interest as variable(s). The data ...
user avatar
3 votes
1 answer
146 views

What is the displacement amplitude of a 140 db sound wave?

I am teaching a unit on sound in my upper elementary science class, and my students are curious about how far air molecules are actually being displaced in a sound wave. I told them that if the air ...
user avatar
0 votes
2 answers
55 views

Could a 100 solar mass black hole at 0.01c passing just at 123 AU change the direction the sun is moving by 90°?

I asked the person claiming to have created this video of such an encounter why this simulation suggests that the sun is moving in a direction that is parallel to the plane of the ecliptic? I'd ...
user avatar
  • 267
1 vote
1 answer
59 views

What is the terminal velocity of coin

Very little work has been done at my office for the past few weeks, as we've been bogged down in a debate on the terminal velocity of a coin (the coin in question is a local one, of 9.2g, 28.5mm ...
user avatar
  • 23
0 votes
0 answers
14 views

Is there a way to estimate the force of this impact?

https://www.youtube.com/watch?v=UKuPuRRNa5Q&ab_channel=BigCatPublicSafetyAct Let's assume that the tiger weighs 500 lbs, is there a way to estimate the force absorbed by its shoulders when it hit ...
user avatar
2 votes
1 answer
63 views

Are there tidal forces between the solar system and the galactic centre?

Tidal forces are experienced within a system moving in free fall around a bigger object because of the different strength of gravity over the system. The difference can be calculated between the far ...
user avatar
-1 votes
1 answer
69 views

How deep is a gravity well of a supermassive black hole? [closed]

Just for the sake of curiosity I am trying to understand how far we should stay away from the black hole to avoid influence of its gravity on us. In the first iteration I know about the 2nd and the ...
user avatar
0 votes
1 answer
36 views

Necessary mass and speed of asteroid required to make Venus spin

Suppose we are going to push a large asteroid (or two) from the belt and use them to make Venus rotate at approximately the same rotational speed as earth. Here are some questions regarding that: If ...
user avatar
  • 101
-5 votes
2 answers
62 views

Which is more: Energy released by nuclear fission or fusion? [closed]

The energy released by one fission reaction is 190MeV and the energy released by one fusion reaction is 24.7MeV. Then by my common sense 190>24.7 so energy released by fission>fusion but the ...
user avatar
1 vote
1 answer
23 views

Is capillary pressure significant?

I have a hydraulic system pressure to be measured in cm of water. It is done by tapping a graded tube, and simply measuring the height of the water column (usually at around 10-20 cm of water). If I ...
user avatar
  • 13
0 votes
0 answers
28 views

How large are the fictitious forces due to our orbit around the galactic center?

When we are in a non-intertial system, this creates fictitious forces. Some well-known fictitious forces are the centrifugal and coriolis forces. Those are caused by the Earth's spin around its axis. ...
user avatar
  • 457
1 vote
1 answer
113 views

How was Enrico Fermi able to predict a power output from his uranium and graphite Chicago Pile 1 (CP-1) reactor?

Uranium and graphite heat engine physics - early detection methods I've been inspired by the early developments in fission heat engines which happened even before uranium enrichment methods were ...
user avatar
0 votes
2 answers
61 views

Could I use magnets to lift or move something from a distance

Would it be possible to use magnets to cause some object to lift off the ground from a meter or two away? Let's assume that material cost is of no concern. What sort of object are you hoping to lift? ...
user avatar
1 vote
0 answers
35 views

Could gravitational waves be cosmologicaly 'redshifted'? [duplicate]

Is it posible that gravitational waves detected here on Earth could be cosmologicaly 'redshifted'? So, at emission they had higher frequency then after reaching Earth?
user avatar
2 votes
0 answers
49 views

Are the rest frames of particles in LHC detectors approximately inertial?

Years ago as an undergraduate, I studied new-physics contributions to the reaction $ cb \rightarrow tb $ in the case that the $t$ subsequently decays as $t\rightarrow be^+\nu_e$. I considered the ...
user avatar
  • 363
4 votes
1 answer
117 views

Considering General Relativity, how long would it take for a ball to stop oscillating dropped through the center of the Earth?

In Newtonian view, if a relatively small mass was dropped through a frictionless tunnel without drag intersecting the center of a non-rotating, spherically symmetric,uniform density Earth, then the ...
user avatar
15 votes
2 answers
1k views

Is CMB slowing down all moving objects in the universe?

1/ Object moving relative to the CMB frame of reference will see the CMB blue shifted where it is heading and red shifted where it came from. Correct? 2/ The blue photons ahead should have more ...
user avatar
0 votes
0 answers
36 views

How many pixels could an image of Proxima b taken by James Webb have?

I know it's very difficult for the James Webb to image Proxima b without a coronograph (I have been told by NASA scientists that they don't know yet whether they will be able to do so), but I wonder ...
user avatar
  • 1
0 votes
4 answers
84 views

What am I doing wrong in this estimation of the mass of the atmosphere?

I'm trying to approximate the mass of the atmosphere. I'm treating it as an ideal gas and therefore its density follows: $$\rho(z) = \rho(0)e^{(\frac{-mgz}{k_BT})}$$ Where I'm using $m=4.2122\cdot10^{-...
user avatar
  • 187
0 votes
0 answers
46 views

Is it likely that objects placed at the Lagrange points of the earth-moon two-body system collide?

Is it likely or unlikely that objects placed at a Lagrange point of the earth-moon two-body system collide? It may be assumed that the objects are not self-propelled and are dynamically influenced by ...
user avatar
  • 2,338
1 vote
0 answers
42 views

Why not use Neodymium magnets in cyclotrons? [closed]

I am wondering if we can make relatively strong cyclotrons /200-400MeV/ far less massive, in the range 10-20t. Why don't we use neodymium magnets in cyclotrons instead of electromagnets? Nd2Fe14B ...
user avatar
  • 11
1 vote
2 answers
49 views

On which speed the relic microwave background radiation becomes dangerous for the people on space ship?

If we travel with speed close to the speed of light, the light waves becomes shorter and their energy increases (because we flight through much more light for the same time). So, even background ...
user avatar
  • 618
0 votes
2 answers
74 views

What is the theoretical setup needed to make a black hole?

What is the theoretical setup needed to make a black hole? Firstly sorry for the broad-ended question. I recently came across this statement from this website. "In theory, any mass can be ...
user avatar
  • 19
0 votes
0 answers
22 views

Calculating kwh required to get an aircraft to 1000' based on climb rate

I'll start with the question and then provide context: to get an aircraft to 1000', does a steeper climb angle consume more energy? Assume the flying speed and angle of attack stay constant. This ...
user avatar
0 votes
0 answers
28 views

How much kinetic energy does it take to break a wooden bollard?

Does somebody have an idea how much kinetic energy it would (approximately) take to break a common wooden bollard (like the one in the picture below). When for example it gets hit during a car crash? ...
user avatar
0 votes
0 answers
12 views

What's the voltage accuracy of tip electrode of modern SEMs (Scanning Electrode Microscope)?

I want to know with what accuracy the potential(or the voltage) of a tip electrode (of a SEM) can be adjusted?
user avatar
  • 101
2 votes
0 answers
65 views

How weak are the Van der Waals bonds? What is their contribution to the total mass of an object?

We know that every binding energy can be expressed as a negative mass contribution to the total mass of the system. It is well known, for example, that composite nuclei have a “mass defect” when ...
user avatar
  • 867
1 vote
0 answers
41 views

Time Scales in the BBGKY Hierarchy

(I am following Chapter 3 of Mehran Kardar's Statistical Mechanics of Particles)When working with the BBGKY hierarchy of equations, we get the following for the two-particle probability density $f_2$: ...
user avatar
0 votes
2 answers
44 views

How can i calculate the compression or deformation of an object after a collision? [closed]

To be more precise about what I want to ask, will an object of 1 kg going at 10 m/s hitting another object of 1000 kg (at rest) have the same deformation as if we switch the velocities and the one of ...
user avatar
1 vote
1 answer
49 views

Percentage of body weight raised for this variation of pull ups?

I have a simple question I think. If one uses one dip bar and do a version of pull ups as follows: what percentage of their body weight is lifted? I.e. how different is it than a regular pull up in a ...
user avatar
  • 111
18 votes
4 answers
17k views

Can our hand pass through a table?

I recently read that "there is a $1$ in $5.2^{61}$ chance that the molecules in your hand and table would miss each other, making your hand go through it". To me, it seems completely false, ...
user avatar
  • 313
1 vote
1 answer
35 views

Will angular velocity of earth be Affected By this? [duplicate]

If all the humans, animals, and all other beings came together to North Pole of earth, Will it affect the angular velocity Of earth in any means?
user avatar
1 vote
0 answers
33 views

How large of a planet could we build a space elevator on?

Currently, we don't know of any material that has a high enough tensile strength to weight ratio to construct a space elevator on Earth. But this has me wondering, with the materials we do have, what'...
user avatar
1 vote
0 answers
59 views

What happens when you heat 5 cubic meters of iron to 3500k in 0.1 seconds?

I've been googling this problem all night. I have no relevant degrees in physics, but I'm fascinated by it. In the Warhammer 40.000 universe there is a portable weapon called a "melta" it is ...
user avatar
2 votes
2 answers
84 views

What would happen if a teaspoon of neutronium crashed through Earth's atmosphere? [duplicate]

Pretty self explanatory hypothetical. I realize this is probably an impossibility and maybe it'd be more likely to be hit by a small black hole or primordial black hole. I'm just curious, because we ...
user avatar
  • 31
-1 votes
2 answers
85 views

Does time go slower as you travel in the air? [duplicate]

I would like to specify a few things before starting with my actual question : At the equator, the Earth spins at approximately $1000 \ \mathrm{mph}$ Currently, because we are on the Earth, even we ...
user avatar
7 votes
1 answer
497 views

What volume would the mass of Earth occupy in the core of the sun?

I was just wondering if anyone had computed this. I read that the pressure in the Sun's core is 3.84 trillion psi. Obviously the mass of an Earth-sized object in the core would be millions of times ...
user avatar
15 votes
7 answers
4k views

Can Heisenberg's uncertainty principle be used to prove the electron can't exist in the nucleus in this way?

This is the solution given in the textbook (my analysis below it): From my understanding, I believe this solution is wrong. My understanding is that the more accurately we know the position, the less ...
user avatar
2 votes
1 answer
77 views

Can weak measurement principles of Quantum mechanics be used in similar questions in classical estimation problems?

This is a surface level question and I don't want to go into detail. Imagine an algorithm which when used with a sensor output gives the statistical moments of a variable in nature (for example mean ...
user avatar
7 votes
2 answers
693 views

The effect of gravitational lensing during the lunar eclipse

During the lunar eclipse, the Moon turns into bloody colour while the shadow of the Earth is casting over the lunar surface. The red hue can be explained by means of the refraction of light and ...
user avatar
3 votes
1 answer
105 views

With how much energy can a charged black hole launch a electron away with?

Lets say with have a black hole with a strong negative charge, then a say a neutron falls towards it. Just before the neutron reaches the black hole's event horizon it undergoes beta decay, this ...
user avatar
  • 1,374
1 vote
2 answers
77 views

How fast can manned spacecraft slingshot from Black Holes?

I've read of Black Holes launching particles at over 99% the speed of light. Could manned spacecraft use Black Holes to slingshot ourselves at this speed, or would the G forces kill us? Intuitively, I ...
user avatar
1 vote
1 answer
42 views

Would light sails be a practical means of travel in the center of Andromeda? [closed]

I've read that at Andromeda's center, stars are only 0.008 lightyears apart from each other. Is this a short enough distance for light sails to be a practical means of space travel, or is this still ...
user avatar
-1 votes
2 answers
98 views

Why didn't I experience violet shift at traffic signals?

context: we were studying sound waves and our instructor informed us about doppler effect and violet shift of light. Now I have many times exceeded the speed limit at night where there were no cameras ...
user avatar

1
2 3 4 5
20