The property of an object that determines how much it responds to a force in Newtonian mechanics, and how much it interacts with gravity in the Newtonian framework. Mass also refers to the intrinsic energy of a particle in particle physics.

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283 views

The (relativistic) mass of a proton in the LHC

What would be the (relativistic) mass of a proton, in grams, as it is traveling at the maximum possible speed in the LHC?
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3answers
95 views

Justification of $P_{\text{photon}}=E/c$ in derivation of $E=mc^2$

I recently was reading up on the derivation of $E=mc^2$. Now, I came across this derivation at this link. I noticed that several lines into the derivation they throw in the equation ...
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3answers
80 views

What are the six quark mass values when extrapolated to Planck energy?

Let us assume that the standard model is correct up to Planck mass. (Yes, I know, this is a big assumption.) If we continue the running of quark masses with energy (due to renormalization), what are ...
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1answer
120 views

Mass of a particle ( relativity)

A hypothetical atom has a rest mass of $15.000000136\,\mathrm{u}$. Overtime it undergoes a spontaneous breakdown into two masses of $7.000000229\,\mathrm{u}$ and $6.902727019\,\mathrm{u}$ ...
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4answers
111 views

Does not the mass of those living on the Earth add on to the mass of the Earth or is it too negligible to be cared for?

Source: Earth weighs about 13,170,000,000,000,000,000,000,000 pounds (or 5,974,000,000,000,000,000,000,000 kilograms). Since Earth is too big to be placed on a scale, scientists use mathematics ...
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70 views

Mass - Unification of kinetic and gravitational mass definitions

As a kinetic definition, mass of a body is a measure of the translational inertia of the body. There is also the gravitational definition of mass. Can these definitions (kinetic and gravitational) be ...
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2answers
101 views

Is a blackhole just a neutrino with much more mass?

If there was a blackhole that had a mass similar to that of a neutrino ($0.320 ± 0.081\,\mathrm{eV/c^2}$), would we still be able to differentiate the blackhole from the neutrino? Is there any ...
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2answers
831 views

Quarks in a hadron- where does the mass come from

We know that the sum of the masses of the quarks in a proton is approximately $9.4^{+1.9}_{-1.3}~\text{MeV}/c^2$, whereas the mass of a proton is $\approx931~\text{MeV}/c^2$. This extra mass is ...
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1answer
68 views

Two-body systems quantum physics (Transformation) [closed]

Given the Schrödinger equation $i\hbar \frac{\partial}{\partial t}\Psi(\vec r_1,\vec r_2,t) =\left [ -\frac{\hbar^2}{2m_1}\nabla_{r_1}^2-\frac{\hbar^2}{2m_2}\nabla_{r_2}^2 +V(\vec r_1,\vec r_2)\right ...
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5answers
1k views

Is it possible for an object to have mass but zero volume?

Can there exist a particle/object in the universe having mass but no volume? Is it possible that mass can exist without volume and density? We think we know that matter is anything having mass and ...
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1answer
63 views

Applying downward force on someone without adding to their weight

I am creating a scenario for a superhero comic, and need help with an idea. I'd like the solution to be based in scientific theory, or at least scientific fantasy, as opposed to resorting to simply ...
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1answer
107 views

Do photons have no mass? [duplicate]

My Quantum Mechanics' teacher said today on the class that photons don't have mass. I was puzzled because I knew that photons have momentum. If a particle hasn't mass then its momentum sould be $0$ ...
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1answer
156 views

Does a rotating object have more inertia, mass and gravitational pull?

When an object is rotating on an axis, it has stored rotational energy in it. Since energy and mass are related, does this stored rotation increase the mass of the object? And if so, will it be harder ...
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2answers
79 views

Planks, supports, and a scale [closed]

I've got two equal dimension planks with the same homogenous mass. They're placed next to each other like this (bird's eye view): [ ][ ] They're sitting ...
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0answers
81 views

Significance of imaginary mass

Can real mass be thought of as producing a deformation in spacetime leading to a stable equilibrium (valley curve in gravitational potential energy) of the massive body, and imaginary mass as similar, ...
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2answers
256 views

Can the up quark still be massless?

It used to be commonly discussed that the bare mass of the up quark can be $0$. This was because we can't observe its effect directly. To my knowledge the up quark can only be measured by its effect ...
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0answers
21 views

Flamant's use of mass and weight

I apologize for the stupid question, but I've consulted teachers and found their answers unsatisfactory. Professor E.Brune, in the XIX century, delivered a course on l'École des beaux-arts on ...
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1answer
455 views

Centre of gravity vs centre of mass for a pyramid mounted on a cube, all sides of length $l$ [duplicate]

A uniform solid body is constructed using a square-based pyramid mounted on a cube. If each edge of the solid has length $l$ show that the centre of gravity of the body lies within the cube is, $\frac ...
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1answer
52 views

Mass to Light Ratios

I know that the mass to light ratio for galaxies is between 2 and 10. I also know that the ratio changes primarily based on what kind of galaxy you have (elliptical, spiral, etc). Is there a table ...
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1answer
98 views

Is the relativistic mass of a photon non-zero?

A photon has rest $m=0$, but it is never at rest, so it has no rest mass, then the relativistic mass is according to me non-zero because: $E = \text{work}=m \times \text{acceleration} \times ...
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1answer
638 views

How is the fall time for a parachute affected by the mass of the load?

Why do parachutes with a heavier load fall faster than a parachute with a lighter load?
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1answer
82 views

is there an operator which measures the mass of particles?

When I studied a spin, the textbook said spin is an intrinsic quantity like mass. However, while we can calculate just expectation values $ \langle \textrm{S}^2\rangle $ or $ \langle S_z\rangle $, the ...
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1answer
239 views

Difference between mass and weight [duplicate]

I already know that when I standing on weighing machine it's measuring my mass not my weight, but when I take the same machine to moon it's will read different value. According to my information that ...
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1answer
58 views

One stupid question about Dirac mass term and Grassmann numbers

Let's have Dirac mass term in lagrangian: $$ L_{M} = \bar{\Psi}\Psi $$ Lagrangian must be real-valued, i.e., its Hermitian conjugation doesn't change it. But due to Grassmann nature of spinor fields, ...
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1answer
75 views

Could the Big Bang have simply been two black holes hitting each other at 99% of the speed of light? [closed]

Given two equally massive black holes moving at 99% of light speed, it seems there would clearly be enough energy for most (99%?) of the mass of both to be ejected and / or radiated well beyond the ...
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1answer
23 views

Would a fast moving (approaching $c$) stream of particles be affected by the gravitational pull of a gas giant?

I was inspired by this SE question. Would the gravitational field of a gas giant (such as Yavin IV) have an effect on the super laser (i.e. slow it down, change the direction), or is the mass so ...
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1answer
190 views

What is the baryonic mass distribution of the Milky Way

There are many, many studies of the Dark Matter halo around the Milky Way but I'm having trouble finding good raw data about visible matter. I'm investigating a MOND like model and would like some ...
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1answer
146 views

Why is centre of mass taken as integral of x.dm and not m.dx?

Forgive me if I'm being naive, but, I don't understand why the X-coordinate of the Centre of mass is taken as an integral of x.dm and not m.dx. I understand the summation part, but how do we convert ...
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1answer
116 views

$U(1)$ local gauge invariance in QED [duplicate]

While constructing Lagrangian of QED, we don't add the mass term for photon $\dfrac{1}{2} m^{2}A_{\mu}A^{\mu}$ because gauge invariance does not allow. I want to ask, whether "$\bf{Theoretically}$", ...
2
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1answer
114 views

Interpretation of negative mass in condensed matter physics

I am reading the book "Topological insulator: Dirac equation in condensed matters" by Shun-Qing Sheng. I do not know much about this topic and this is the first time I am confronted with it, so this ...
3
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2answers
262 views

Can you express mass in other dimensional units?

I'm just started a Physics I course, and while I've paid attention, I'm stuck on one of the first problems: Express mass ($M$) in terms of acceleration($a$), density($D$), area($A$), and time($t$). ...
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4answers
320 views

Is there difference in force when the height increases?

Consider a man with mass 50kg. When he jumps from a 2 meter height, the total force is $F=ma$ ie (mass * gravity), but nothing happens to him. When he jumps from a 50 meter height, the total force ...
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2answers
72 views

What objects' masses do we need to take into account when calculating force?

In the following problem: A steam engine of mass $3\times 10^4\ \mathrm{kg}$ pulls two wagons each of mass $2\times 10^4\ \mathrm{kg}$ with an acceleration of $0.2\ \mathrm{m/s^2}$. Neglecting ...
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0answers
26 views

Local Gauge Invariance and Masslessness [duplicate]

I am wondering if the masslessness of photons is due to the local gauge invariance of $u(1)$-gauge fields. The reason why I consider about this question is that I remember that the Proca field is not ...
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2answers
118 views

Save a falling person by nullifying their mass or reversing gravity [closed]

Let's say you have the superpowers to manipulate matter, mass and gravity. Imagine a person falls off a plane, flying few kilometers above the air, and they are about to get splattered onto the hard ...
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1answer
137 views

Why cannot massless particles carry charges? [duplicate]

How to show that massless particles do not carry charges from QFT's point of view?
2
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1answer
55 views

Particle masses

if there is no theory to predict/calcukate the masses of the fundamental particles, where do they get the values for the quarks, as quoted in the standard model? And since the composite particles get ...
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2answers
447 views

Is most of the matter in the observable universe within galaxies?

Do we know, either through observations or through theory driven computer simulations, the location of the majority of the visible matter in the observable universe? That is, is it located within ...
2
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3answers
528 views

Is the Higgs field needed to explain the mass of the electron?

The self energy of the electron can be represented in two ways: the energy required to bring a charge distribution from infinity to the size of the electron (assuming it is a point charge with no ...
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0answers
41 views

Distance and Time

I understand that if an object is 10 light years away then the light I am seeing from that object is actually from 10 years ago. If this is the case, which a few posts on this forum seem to concur, ...
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6answers
143 views

A contradiction statement to $F=ma$ [closed]

If I thrown an object of mass 1 kg up in the air it will always fall with an acceleration of 9.8m/s. If I throw it very high up in the sky, it falls with a greater force as compared to if i throw it ...
1
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3answers
813 views

Neutrinos have mass. But how much mass?

Can somebody explain to me how much mass neutrinos have. According to my understanding neutrinos oscillate, therefore they should have some mass. If this is right then how much mass do they have?
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1answer
161 views

Is the sum of mass of all planets in our solar system is 40% the mass of the Sun? [closed]

According to Chandrasekhar Limit,the mass of an object can not exceed than 1.4 times the mass of the sun.But according to some other theories,the sun was very large at former times and earth and ...
2
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0answers
108 views

Is the Higgs field responsible of only 1% of the proton mass?

This post is a sequel of: Where does the majority of the mass of the usual matter come from? The following answer of @hft: Your question asks why the "current quark masses" [see ...
2
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1answer
73 views

Why couldn't a space elvator's cable be tapered?

Why couldn't a space elevator's cable be tapered to solve the weight issue for the cable? After all you don't need a massive amount of tensile strength at the bottom of the cable.
2
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2answers
81 views

Will the gravitational pull of air affect the falling rate of an object?

After looking at this question: Don't heavier objects actually fall faster because they exert their own gravity? A thought occurred to me that due to the increased gravitational pull of the ...
0
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1answer
124 views

What force causes massive objects to bend space? [duplicate]

The visualization of gravity as shown by this video is pretty good at explaining how massive objects bend space, and such bending causes objects around it to fall towards it (a.k.a: gravity). ...
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2answers
119 views

Why is a silicon ball with an exact number of atoms a bad measure of mass?

I have some friends that are talking about why a silicon ball with an exact number of atoms is a good/bad measurement of mass (1kg) and things are getting pretty exotic. Is there a layman's ...
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1answer
113 views

Can mass-less spring system be solved?

Suppose we have typical chain of strings with masses, attached to the walls (W) at each side W-----m-----m--------W x=0 x=6 x=12 x=21 So if we let ...
0
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1answer
110 views

Does an object traveling near the speed of light create a gravitaional field? [duplicate]

Does a particle traveling near the speed of light create an observable/measureable gravitational field around it? I know most elementary particles travel near the speed of light and have no ...