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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1answer
294 views
Archimedes principle and specific gravity
A physical balance measures the gravitational mass of a body. I conducted an experiment to find out the specific gravity of a bob. I first measured the mass of the bob in air, and then in water. The ...
2
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6answers
2k views
Why can't photons have a mass
Why can't photons have a mass? Could you explain this to me in a short and mathematical way?
2
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1answer
79 views
Complex masses for Dirac and Weyl spinors
I'm trying understand how to rotate Dirac fields to absorb complex phases in masses. I have a few related questions:
With Weyl spinors, I understand, $$ \mathcal{L} = \text{kinetic} +
...
1
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0answers
25 views
Finding the force of an object? [closed]
Sorry if my initial question was seen as a "homework question" but I don't really know how to go about asking this type of question. I have a feeling I have to use Newtons law but there is no ...
2
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1answer
105 views
Doubts about the definition of mass
I'm having some problems understanding what are the possible definitons of mass and how they are related to each other.
In Classical Mechanics, we can distinguish between inertial and gravitational ...
1
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4answers
587 views
Does matter with negative mass exist?
Or does it exist mathematically?
Is it really inconsistent with a common-sense, mathematics or known physical laws?
As far as I understand, if it exists, it must be far away from the "positive" ...
5
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3answers
243 views
Negative Mass and gravitation
Since Newtonian gravity is analogous to electrostatics shouldn't there be something called negative mass? Also, a moving charge generates electric field, but why doesn't a moving mass generate some ...
4
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1answer
104 views
Mass gap for photons
I am puzzled by the answers to the question:
What is a mass gap?
There, Ron Maimon's answer gives a clear-cut definition, which I suppose applies to any quantum field theory with Hamiltonian $H$, ...
4
votes
3answers
108 views
Moment of Inertia (triangular plate)
I want to generalize the formula for the MOI of a triangular plate (sides $a,b,c$) about an axis passing through mid point of one sides and perpendicular to it's plane .
The mass of plate $M$ is ...
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1answer
55 views
Does the magnitude of a mass affect the velocity?
Imagine that I shrink my entire mass to fit within the volume of a light particle. If I was then 'hit' by another light particle would my greater mass affect my gain in velocity from this collision ...
1
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1answer
89 views
Does mass concentration affect the torque induced by a force?
If you had two bodies with the same weight but one having mass concentrated more in the center, while the other had most mass concentrated on the outside, but both had the same center of mass and ...
4
votes
3answers
118 views
Precision of Coulomb's law
Up to which precision has the coulomb law proven to be true?
I.e. if you have two electrons in a vacuum chamber, 5 meters appart, have the third order terms been ruled out? Are there any theoretical ...
2
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2answers
85 views
Does inertia increase with speed?
I have heard that when the speed of the object increase, the mass of the object also increase. (Why does an object with higher speed gain more (relativistic) mass?)
So inertia which is related to ...
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1answer
48 views
Center of mass of three particles of masses 1kg, 2kg, 3kg lies at the point (1,2,3) [closed]
Center of mass of three particles of masses 1kg, 2kg, 3kg lies at the point (1,2,3) and center of mass of another system of particles 3kg and 2kg lies at the point (-1,3,-2).
Where should we put a ...
2
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2answers
535 views
Why does an object with higher speed gain more (relativistic) mass?
Today, in my high school physics class, we had an introductory class on electromagnetism. My teacher explained at some point that an object with a very high speed (he said it started to get somewhat ...
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0answers
50 views
Why does an object with higher velocity gain more mass? [closed]
if we inject pure energy into a object capable of moving will it affect the structure of its atoms creating bigger neutrons, electrons and protons making the object increase its size affecting its ...
1
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1answer
53 views
Defining the star as the ellipse focus rather than the barycenter, what does the other focus do? [duplicate]
There are a lot of images and animations on the internet depicting two bodies orbiting around their common barycenter. The barycenter is defined as the (let's say right) focus of the ellipse.
If we ...
0
votes
3answers
79 views
Mass in special relativity
I have just got a query about how this equation works if its right.
We have Newtonian Physics saying $F=ma$,
According to the 'Mass in special relativity' the mass changes according to
$$m= ...
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1answer
116 views
Why does Lorentz factor not hold for relativistic mass when we apply it to photons? [duplicate]
We know that the photon itself is massless particle $m_0=0$. But we also know, that the mass of the objects does increase with their energy. And we know that under certain circumstances (gravity, ...
10
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2answers
286 views
Does relativistic mass have weight?
If an object was sliding on an infinitely long friction-less floor on Earth with relativistic speeds (ignoring air resistance), would it exert more vertical weight force on the floor than when it's at ...
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9answers
6k views
Why does the mass of an object increase when its speed approaches that of light?
I'm reading Nano: The Essentials by T. Pradeep and I came upon this statement in the section explaining the basics of scanning electron microscopy.
However, the equation breaks down when the ...
5
votes
3answers
109 views
Is it possible to have a singularity with zero mass?
A singularity, by the definition I know, is a point in space with infinite of a property such as density.
Density is Mass/Volume.
Since the volume of a singularity is 0, then the density will thus ...
2
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2answers
123 views
Have negative pressures any physical meaning?
Some cubic thermodynamical equations of state predict negative pressures, have negative pressures any physical meaning? Could they be related to negative mass?
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4answers
1k views
Acceleration of two falling objects with identical form and air drag but different masses
I have a theoretical question that has been bugging me and my peers for weeks now - and we have yet to settle on a concrete answer.
Imagine two balloons, one is filled with air, one with concrete. ...
4
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2answers
148 views
How can a pion have a mass, given it's a “field mediator” and created/destroyed continuously?
Maybe some of my assumptions here are basically wrong, but isn't it true that
pion is the "mediator" for the strong force field.
the quantum field theory basically says that there are no fields, ...
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1answer
81 views
Is the speed of light related to the mass of the universe?
If the mass of the universe were cut in half, would it affect the speed of light?
Would it be twice as fast?
Would it stay the same?
Do we have instruments that are sensitive enough to measure the ...
8
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1answer
156 views
How the inverse square law in electrodynamics is related to photon mass?
I have read somewhere that one of the tests of the inverse square law is to assume nonzero mass for photon and then, by finding a maximum limit for it , determine a maximum possible error in ...
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2answers
89 views
Do photons have mass? [duplicate]
As a student in a highschool physics class, my teacher has repeatedly told me that photons are massless. Yet, I have also heard from other sources that photons have momentum. If photons were to have ...
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0answers
24 views
if greater mass equates to greater force, a heavier perso would have more force potential than a skinnier one? [closed]
In physics laws greater mass is usually associated with greater force, such as dropping a bowling ball on your feet and dropping a gum ball. The bowling ball has more atoms, and is solid metal, so no ...
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votes
0answers
23 views
Does ability to lift more weight mean more physical strength? [closed]
so I thought this question is physics-related, so why not elaborate here.
Muscular strength can be combined not just by muscle mass but density, neuromuscular conditioning, joints, leverage, etc.
So ...
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1answer
38 views
Period of oscilation [duplicate]
Two masses $m_1$ and $m_2$ are connected by a spring of spring constant $k$ and slide freely without friction along horizontal track. What is period of oscillation? No force influence.
3
votes
2answers
185 views
System of Particles and Moment of Mass
I recently came across the definition of the Center of Mass of a system as the point about which the first moment of mass is zero.
Further, it defined Moment of Inertia as the second moment of mass.
...
2
votes
2answers
49 views
Can the effects of a person's mass upon the local gravitational field be detected and measured remotely?
As the title suggests, Can the effects of a person's mass upon the local gravitational field be detected and measured remotely?
I am aware any mass produces and effects gravity but couldn't find ...
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4answers
677 views
Is the earth expanding?
I recently saw this video on youtube:
http://www.youtube.com/watch?v=oJfBSc6e7QQ
and I don't know what to make of it. It seems as if the theory has enough evidence to be correct but where would all ...
4
votes
1answer
97 views
Soft Mass and Physical Mass in Softly-broken SUSY
In softly broken SUSY, the bare mass parameters may be specified at e.g. the GUT scale, and then we can run these down to another scale using RGEs, similar in form to the RGEs for gauge couplings, ...
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1answer
40 views
Mass of a jumper, given height jumped and force exerted [closed]
This is the question:
An exceptional vertical jump from rest would raise a person 0.83m off
the ground. To do this, a constant force of 2593N would need to be
exerted against the ground. ...
0
votes
2answers
98 views
What is the mass of a photon moving at the speed of light? [duplicate]
What is the mass of a photon moving at the speed of light?
And if it does not have mass, how is it affected by gravity?
Also why does Einstein's general relativity support that a gravitational wave ...
4
votes
1answer
86 views
How did Newton find out force has something to do with acceleration?
Its about Newton's second law of motion,
$$F=ma.$$
It says the acceleration of an object is directly proportional to the net force and is inversely proportional to the object's mass. Yes I can ...
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3answers
77 views
Mass equals Moment of inertia when constant density?
I have found equation for moment of inertia $(J)$. I'm calculating $J$ for hemisphere, with rotational axis $Z$.
$$ J = \iiint\limits_V r^2 \cdot \rho \cdot dV $$
But if $\rho$ is constant ...
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3answers
148 views
What truly is mass, and is there a direct way to measure it?
We know a mass of an object of one kilogram as an object that weighs W = mg = 9.8 N and we reference it to that, (when it should as a fundamental parameter describe weight not the opposite). But if we ...
1
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1answer
54 views
A sphere, a simple object?
In this video, the woman says that a sphere is a pretty simple object. What intrigues me is the use of a sphere for such a calculation. First of all, the sphere wouldn't be perfect as a perfect sphere ...
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votes
1answer
61 views
How do we know that light is massless? [duplicate]
Almost everybody knows that light is massless. But where this come from and how it can be proven (experimentally or theoretically)? I actually found this article which explains and calculates the mass ...
32
votes
7answers
2k views
Why do we have an elementary charge but no elementary mass?
Why do we have an elementary charge $e$ in physics but no elementary mass? Is an elementary mass ruled out by experiment or is an elementary mass forbidden by some theoretical reason?
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votes
3answers
219 views
Does a photon have mass? [duplicate]
I have seen questions assume photons have no mass. But I have not seen any questions that directly ask whether or not photons have mass.
If photons have no mass, then how do they occupy space? How ...
4
votes
1answer
81 views
Mass-energy equivalence and Newton's Second Law of motion
According to Einstein's Mass-energy equivalence,
$ E = mc^2$ OR
$ m = \frac E{c^2}$..... (1)
and According to Newton's Second Law of motion,
$ F = ma$ OR $m = \frac Fa$ ..... (2)
If we compare eq. ...
6
votes
3answers
509 views
Special Relativity and $E = mc^2$
I read somewhere that $E=mc^2$ shows that if something was to travel faster than the speed of light then they would have infinite mass and would have used infinite energy.
How does the equation show ...
10
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10answers
3k views
Does 'electricity' have mass? Is 'electricity' tangible?
Background: I'm in a legal academic discussion about the status of electronic 'goods' and whether they qualify as 'goods' in the same way a chair and a pen do. In this context (and specifically at the ...
4
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4answers
310 views
Relativistic mass and imaginary mass
The (relativistic) mass of an object measured by an observer in the $xyz$-frame is given by
$$m = \frac{m_{rest}}{\sqrt{1 - \left(\frac{v}{c}\right)^2}}.$$
Mathematically $v$ could be greater than the ...
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votes
4answers
125 views
Does everything with mass or energy have a gravitational pull?
As small as it may be, does every 'thing' have a gravitational pull? That is, something with mass or energy. No matter how obsolete or negligible it may be, is it there? If so, how is it calculated? ...
11
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4answers
880 views
Why does a black hole have a finite mass?
I mean besides the obvious "it has to have finite mass or it would suck up the universe." A singularity is a dimensionless point in space with infinite density, if I'm not mistaken. If something is ...
