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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Classic mass predictions from Left-Right models with discrete symmetries?

I am covering the classic literature on predictions of Cabibbo angle or other relationships in the mass matrix. As you may remember, this research was a rage in the late seventies, after noticing that ...
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3k views

Is there a finite amount of mass in the universe? [duplicate]

So, I'm not too physics savvy but I am curious to ask. Is there a finite amount of mass in the universe? or is there more and more being created from somewhere or something? If the universe is ...
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5answers
724 views

Does $p=mc$ hold for photons?

Known that $E=hf$, $p=hf/c=h/\lambda$, then if $p=mc$, where $m$ is the (relativistic) mass, then $E=mc^2$ follows directly as an algebraic fact. Is this the case?
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8answers
1k views

Does the (relativistic) mass change? Why?

I learned recently that when an object moves with a velocity comparable to the velocity of light the (relativistic) mass changes. How does this alteration take place?
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2answers
308 views

Is there a connection between gluons and photons?

I was wondering if there is any sort of connection between a gluon and a photon since they are both considered massless.
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4answers
828 views

What is difference between Inertial mass and gravitational mass [duplicate]

I recently read that the mass we deal with in Equation $F=Ma$ is called inertial mass and the mass we deal with in $F=Mg$ is gravitational mass. Suppose I am taking a same ball in a free fall and in ...
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319 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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653 views

Why does the Standard Model predict Neutrinos are massless?

Why are neutrinos massless in the Standard Model? Is it connected with experimental fact that neutrinos always have only one direction of projection of spin on motion direction?
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3answers
487 views

Is a spinning object heavier than a non-spinning object?

Does spinning an object make it heavier? A real-world example: I was mowing the lawn in front of my house, a lawn that tends to have some steep inclines. I realized that the lawn-mower was easier ...
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1answer
404 views

How quickly does gravity extend from created mass? [duplicate]

I apologize in advance if this is a stupid or off-topic question. Since Energy can be converted into matter according to $E=mc^2$, how fast does it take for the gravity of that new matter to extend ...
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2k views

Is it possible to calculate weight of person with sensors found in today's smartphone?

Is it possible to calculate the weight of a person by only using his smartphone, some action he must perform (jump, rotate etc.) and some data like his height or age. Current smartphones have the ...
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2answers
467 views

Why are particles different sizes?

Is it correct in saying that a particles size is it's rest energy, and that particles don't actually have size (in the way you get different size objects)? What defines what sizes a particle can be? ...
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3answers
629 views

What does “nearly infinite mass” mean?

I am sure this is a silly question, but I was reading something that described the pre big-bang universe as having "nearly infinite mass." How can something be "nearly" infinite? The term seems to ...
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2answers
384 views

If a photon has no mass, how can it be attracted by the Sun?

I read that the photon doesn't have mass, but my teacher says that the photon has mass because the sun can attract it (like in the experiments to prove the theory of relativity). I think that there ...
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2answers
357 views

Why should mass be attractive in nature?

Why does a mass attract all the masses around it? Why should't it repel or just stay calm? Why should it be like that?
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2answers
2k views

Higgs-Boson/Graviton [duplicate]

The Higgs boson gives particles mass. And the graviton is the theoretical force-carrier of gravity. Gravity depends on mass. So if the Higgs Boson gives things mass, it therefore gives them gravity. ...
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Do we say that phonon has effective mass through its dispersion relation?

The effective mass is proportional to the second derivative of the dispersion relation d2k/dE2. Do we say that phonon have effective mass through it ? Spin wave have.
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3answers
1k views

Does a toy top weigh less when it is spinning?

I am under the understanding that a toy top will weigh less when it is spinning. The Russians made a spinning type transport back in the 70s to lessen its payload over the tundra. Is this an effective ...
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2answers
225 views

How to find the center of mass of several objects in a 2d plane?

We have the following scenario in a 2d plane: a big rectangle with a lot of smaller similar uniform rectangles in it, all of them weight differently. Where is the center of mass of this object ...
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329 views

Does string theory pose a photon mass problem?

A few weeks ago, I started reading books on string theory. One thing that really seemed confusing or contradictory was that string theory explains that the energy of a superstring gives mass to the ...
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5k views

Orbital speed for a circular orbit?

I wanted to look up the formula for orbital speed for a circular orbit on Wikipedia, and I found 2 formulas: All bounded orbits where the gravity of a central body dominates are elliptical in ...
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1answer
235 views

Photon mass and life time

In this article, the author tried to explain that, Einstein's theory may not valid because he says "photon can decay because it may have minute amount of mass". I'm totally in a conundrum state that ...
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2answers
190 views

Strings and their masses

How do strings present in particles give mass to them? Is it only by vibrating? I have been trying to find the answer but could not find it anywhere, can this question be answered?
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3answers
9k views

All matter has a mass but does all matter have a gravitational pull?

I know that all planets and stars have a gravitational pull but does a simple much smaller object have a gravitational pull for example a pebble?
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74 views

What would be the photon's effective mass in Newton's Law of Gravitation?

If we equalize the force from the Newton's Law of Gravitation to Force on a photon in a gravitional field (I don't know if there is an equation for it). What would be the photon's effective mass? (I ...
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1answer
157 views

Why is the Earth's moon so big?

It could just be me, but it seems like our Moon is WAY bigger than it should be for a planet of our size. If you look at satellite-to-planet mass ratios for the largest moons of Jupiter, Saturn, ...
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1answer
64 views

Glashow-Weinberg-Salam mass terms

At the end of spontaneous symmetry breaking I get these mass terms: $$W_{\mu}^{\pm}=\frac{1}{\sqrt{2}}\bigl(W_{\mu}^{1} \mp i W_{\mu}^{2} \bigr )$$ $$\mathcal{L}_{mass}=\frac{1}{2} g^2 \frac{v^2}{4} ...
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486 views

Electromagnetic factors affecting inertial mass of a body affect its gravitational mass or not?

We can see that when a charge sphere is at rest & we are to put it in motion with any desired velocity than we will have to apply the same force for a longer time as if it were applied to the ...
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2answers
154 views

How can we get the mass of an uncharged proton?

How can we get the mass of an uncharged proton, i.e. how varies the mass of the charged proton if i remove the electric charge? For the isotopic spin theory neutron and proton have the same mass and ...
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2answers
264 views

Does relativistic mass exhibit gravitiational effects?

Groundhog Day Update, 2014 The simple and dumb way to ask my main question is this: If something like a neutron start goes sailing by at very close to the speed of light, say fast enough to double ...
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1answer
163 views

What is the difference between baryonic and gravitational mass?

I was reading a webpage on neutron stars, and it mentioned that a neutron star's gravitational mass is about 20% lower than its baryonic mass due to gravitational redshift. I understand the basics of ...
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1answer
179 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 ...
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1answer
512 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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1answer
802 views

What bends fabric of space-time?

I know that mass can bend fabric of space-time, which causes gravity by making an object curve around a planet or star but is there anything else that can bend it? Other energy sources, forces ...
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348 views

Dropping cubes of same masses but different sizes?

Two cubes of the same mass but different sizes (smaller Cube A and bigger Cube B) are dropped from same height on to a tray of sand.Which cube will create a deeper impression and why?
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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 ...
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5answers
131 views

Mass and Energy

Would the mass of burnt firewood be equal to the mass of firewood before burning? Then where does that heat come from? According to Einstein's equation, $E=mc^2$ Shouldn't there be some mass going ...
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1answer
181 views

How much weight can a person carry to avoid being blown over by wind?

I wonder if there is a certain amount of weight that I could carry in a rolling bag to help prevent me from being knocked over by the wind. I have balance problems and some lack of muscle strength in ...
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1answer
254 views

Why is Planck mass much larger than the smallest mass that we actually know about?

The three fundamental constants $h$, $c$ and $G$ are manipulated and rearranged in different ways to get the Planck time, Planck mass etc. The Planck time is said to be the smallest time possible and ...
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2answers
167 views

Gravitational distortion of an object's diameter, at a distance,

Does the curvature of space-time cause objects to look smaller than they really are? What is the relationship between the optical distortion and the mass of the objects?
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2answers
6k views

Modeling a two-mass, spring, damper system

I'm trying to model a system with two masses, two springs, two dampers, and one applied force using transfer functions. I'll then be inputting it into Simulink. The system looks like this but there ...
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441 views

storing energy (as mass)

When chemical energy is released mass is reduced, if only by a negligible amount. Presumably that's true for all energy. And presumably that works in reverse as well: storing energy involves an ...
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Why does reduced mass help when talking about two body problems?

I hear people say that reduced mass, $\mu$, is used for two body problems, but what sort of problems? Is it so that the two body system can be treated as one body or is it to simplify calculations ...
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1answer
106 views

The FRW universe is NOT asymptotically flat? Its mass?

The Friedman-Robertson-Walker (FRW) metric in the comoving coordinates $(t,r,\theta,\varphi)$ which describes a homogeneous and isotropic universe is $$ ds^2\,= -dt^2+\frac{a(t)^2}{1-kr^2}\,dr^2 + ...
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1answer
99 views

Photon Mass Term in Schwinger's 2D QED Model

Why does the vacuum polarization in 2D massless Fermion QED, $$ i\Pi^{\mu\nu}(q) = i(\eta^{\mu\nu}-\frac{q^\mu q^\nu}{q^2})\frac{e^2}{\pi}, $$ have the structure of a photon mass term, as is ...
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378 views

Determination of mass density distribution of an object

This is a follow-up to a previous question How can you weigh your own head in an accurate way?. My purpose is not to restart the flurry of more or less humorous jokes (which are not such a bad thing ...
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4answers
17k views

Relationship between mass, energy, and a force?

I've never truly understood the relationship between mass, energy, and force. I know what each of the three are, I just don't fully understand how they interact with each other. For example, How ...
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2answers
804 views

Where does the mass term come from in the Proca Lagrangian?

There are many good books describing how to construct the Lagrangian for an electromagnetic field in a medium. $$ \mathcal{L}~=~-\frac{1}{16\pi}F^{\mu\nu}F_{\mu\nu}-\frac{1}{c}j^{\nu}A_{\nu} $$ ...
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518 views

Does the Photino have mass or is it mass-less like the photon

Does the photino in super-symmetry have a mass, Or is this different in different super symmetric models?
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1answer
161 views

Neutrino Oscillation and their gravitational implications

As I understand neutrinos, there are three different flavors, all with different masses. Although the masses of these neutrinos have not been directly measured, their mass differences have been. ...