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
101 views

Since when the term 'mass' is being used in physics?

I was wondering who used the term 'mass' in physics and in what context? The Online Etymology Dictionary says it is in use since 1704. According to the Wiki article the year is contemporary to the ...
1
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1answer
1k 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 ...
4
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1answer
208 views

Relation of Higgs couplings to masses of fundamental particles

The standard model has 12 massive leptons and 2 massive bosons other than the Higgs. My understanding of the Higgs mechanism is at about the level of this article, which goes as follows. Start with ...
3
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1answer
189 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} + ...
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4answers
218 views

Conversion of mass and energy

First of all I am not a scientist and all these doubts are coming from my curiosity. When Googling about Einstein's $E = mc^2$. I understand that mass and energy are convertible. What it exactly ...
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2answers
372 views

Why do neutrinos propagate in a mass eigenstate?

I am aware that flavor $\neq$ mass eigenstate, which is how mixing happens, but whenever someone talks about neutrino oscillations they tend to state without motivation that when neutrinos are ...
3
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3answers
2k views

Mass of particle near light speed in a medium

I am trying to get a common understanding from these two previous questions: Why does the mass of an object increase when its speed approaches that of light? What happens if light/particles exceeded ...
15
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2answers
2k views

Does a photon exert a gravitational pull?

I know a photon has zero rest mass, but it does have plenty of energy. Since energy and mass are equivalent does this mean that a photon (or more practically, a light beam) exerts a gravitational pull ...
2
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3answers
530 views

How does energy convert to matter? [duplicate]

To my understanding, matter and energy are one and the same. Shifting from $E$ to $M$ in Einstein's famous equation requires only a large negative acceleration. If $M$ really is $E/c^2$, does that ...
2
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2answers
4k views

Does a scale measure weight or mass? [closed]

What does a measuring scale measure: mass or weight? I mean, when we stand on a weighing scale the reading we get is in $\mathrm{kg}$'s. What does this mean?
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3answers
147 views

Question about negative mass [duplicate]

How is it possible to have negative mass for negative mass means something that has less mass even than nothing ? Does nothing has mass? And how is nothing a reference.
4
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1answer
229 views

Imaginary masses

While watching this video, at around 5:00, the man mentions a certain type of particle having imaginary mass. He also says that these kind of particles can go faster then light. But how it is possible ...
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3answers
847 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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4answers
1k views

Is the Woodward effect real?

Did anyone ever heard about this?I've never seen any serious physicist talk about "mass fluctuations". Here is the man in his own words: http://www.intalek.com/Index/Projects/Research/woodward1.pdf ...
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3answers
232 views

The impossible possibility - weightless mass

I have a hypothetical question about inertia. Let's say I have an object with inertial mass a ton (2,000 lbs.), and it is sitting in my front yard, for instance. If it would suddenly become immune ...
2
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1answer
232 views

Neutrino mass with Dirac and Majorana

Why both Dirac mass and Majorana mass terms are needed to explain the mass of a neutrino?
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6answers
4k 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?
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0answers
66 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
159 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 ...
2
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4answers
3k 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
323 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 ...
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1answer
110 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 ...
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1answer
226 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
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3answers
192 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
939 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
140 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
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3answers
184 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= ...
1
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1answer
269 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, ...
5
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3answers
255 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 ...
3
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1answer
361 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
3k 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
votes
2answers
193 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, ...
0
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1answer
144 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 ...
10
votes
1answer
306 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 ...
1
vote
2answers
232 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 ...
0
votes
1answer
74 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.
2
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2answers
106 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
853 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
133 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, ...
0
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2answers
945 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 ...
5
votes
1answer
250 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 ...
0
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3answers
211 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 ...
2
votes
3answers
253 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
vote
1answer
77 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 ...
-1
votes
1answer
104 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 ...
-3
votes
3answers
657 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
238 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
662 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 ...
4
votes
4answers
647 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 ...
3
votes
4answers
935 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? ...