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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2answers
125 views

Point masses and infinite densities

Point masses are masses who don't have volume. It is said that they are infinitly dense, but I though division by zero is undefined hence you can't define the density for a point mass because ...
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1answer
662 views

Why do some particles have a greater mass than others?

The property of mass that almost every particle possesses comes from the Higgs Field. It is this field, which permeates all of space, that particles interact with and hence obtain mass. But why do ...
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2answers
46 views

Are high redshift masses corrected for relativistic mass dilation? They would appear more massive right?

A distant quasar would be less massive in its frame of reference than our observations would suggest. Are such highly red-shifted objects corrected for relativistic mass dilation?
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1answer
115 views

Why do charge on an object remains unaffected by the motion of the object?

Unlike mass, the charge on an object is said to be unaffected by the motion of the object. This statement in my text book, is not yet understood by me. I don't know theory of relativity. On ...
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2answers
383 views

Charge to mass ratio inversely proportional to curved path radius?

In a cloud or bubble chamber, charged particles follow circular paths. I learned that charge to mass ratio of the particles is inversely proportional to the radius of the path. Thus, a particle ...
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1answer
103 views

What happens when half of an orbiting object's matter is annihilated?

Suppose object A orbits object B, and that there are no outside gravitational influences non-Sun gravity influences, and that object A is completely spherical and its mass is evenly distributed. Now, ...
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2answers
452 views

If nothing weighs something then doesn't that mean there is mass associated with spacetime?

Lawrence M. Krauss says, "If you removed all of the particles, all of the radiation,absolutely everything from space and all that remained was nothing that nothing would weigh something." What ...
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2answers
432 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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1answer
107 views

Mass is rigidity?

In General Relativity, a totally rigid body cannot be accelerated. It will behave like something of infinite mass. Similarly a body of two separated particles which connected to each other with a ...
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2answers
885 views

What is the difference between 'running' and 'current' quark mass?

When looking at the PDG, there is a difference between the 'running' and the 'current' quark masses. Does anyone know which is the difference between these two?
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3answers
265 views

Einstein equation $E=mc^2$: Does it mean an object without mass does not have energy?

Einstein equation $E=mc^2$ where $E$ is energy, $m$ mass, and $c$ the speed of light in vacuum. So does it mean objects without any mass does not posses energy for eg lights photons does not have mass ...
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2answers
174 views

Speed of light, lasers and mass

Hopefully this isn't a bad question. Light travels at the speed it does and nothing else can travel that fast because things have mass, correct? Or at least correct on an elementary level. And if ...
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1answer
266 views

Question about Majorana fermions

I have a few questions about Majorana fermions. What is Majorana mass? Does it have a different value compared to the mass in the Dirac equation for an arbitrary fermion? How exactly do they differ? ...
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0answers
35 views

Good and simple reference for studying about ADM mass [duplicate]

I need a good and simple reference for studying about ADM mass. Can someone introduce me one?
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2answers
580 views

Equivalence of definitions of ADM Mass

ADM Mass is a useful measure of a system. It is often defined (Wald 293) $$M_{ADM}=\frac{1}{16\pi} \lim_{r \to \infty} \oint_{s_r} (h_{\mu\nu,\mu}-h_{\mu\mu,\nu})N^{\nu} dA$$ Where $s_r$ is two ...
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5answers
767 views

Why can't missing mass be photons?

After a star lives and dies, I assume virtually all of it's mass would be photons. If enough stars have already lived and died, couldn't there be enough photon energy out there to account for all the ...
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0answers
87 views

On motivation for the definition of ADM mass

The ADM mass is expressed in terms of the initial data as a surface integral over a surface $S$ at spatial infinity: $$M:=-\frac{1}{8\pi}\lim_{r\to \infty}\int_S(k-k_0)\sqrt{\sigma}dS$$ where ...
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2answers
188 views

How is it possible to move something without completely lifting it?

For example, let's assume a chair here: It can be "slid" across the force if we use minimal upwards force, but not enough to actually "lift" the chair. Why should it move? Here's a better example: I ...
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4answers
12k 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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1answer
1k views

Calculate Mass based on Velocity and Acceleration

I am attempting to design a obstacle avoidance system with the Arduino. My position (for now) is going to be stationary. I will be detecting an incoming object and I want to use the below known ...
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1answer
215 views

How did Newton find the relationship between force, mass and acceleration? [duplicate]

I have been told always that $F$ is directly proportional to acceleration. My question is that for finding such a relationship there should be source that produces desired force and in which the ...
3
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0answers
71 views

Commercial large scale production of graphene

I am a third year undergraduate Physics student, and for my solid state physics course I am asked to give a short (10 minute) qualitative presentation on the current standings of graphene production, ...
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2answers
303 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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0answers
43 views

In a windy weather on the beach, is it better to play volleyball with a Ball with more Air or less Air? [closed]

I was wondering, in a windy weather on the beach is it better to play volleyball with a fully blown ball or a ball filled with less air? What are the important factors that make a ball float easier ...
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5answers
1k views

Planck mass is about the mass of one eyebrow hair

Unlike most Planck units named after "Planck" such as Planck length, Planck temperature, etc, the Planck mass seems more closed to daily life. It is about $10^{-5}$g, same order of magnitude of one ...
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1answer
47 views

How is the centre of mass of a Positronium associated with that of an electron and positron?

How is the centre of mass of a Positronium likely associated with that of an electron and positron?
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1answer
189 views

Change in weight by the change in mass of Earth and its radius [closed]

If the mass of Earth is four-times bigger, and the radius of Earth is two-times smaller, what would be my new weight compared to my current weight?
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4answers
8k views

Why is force described as rate of change of momentum? [closed]

momentum = mass * velocity Differentiating both sides leads to force = mass * acceleration since the mass doesn't participate in the differentiation as it is constant. Is this a sound ...
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2answers
114 views

almost same mass, same distance, different energy needs

Imagine a car, driving 10 km at constant speed in 6th gear. There will be a measurable fuel consumption. Now imagine the same car driving 10 km again at a constant speed (same as above) in the 1st ...
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2answers
154 views

Feynman Diagrams: Mass Conservation

Can a Feynman diagram end with more matter than it began with? The answer should be no because it would break the law of conservation of mass, right? Example: I learned that two up-quarks could ...
4
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1answer
148 views

Topological Mass Generation Mechanism

What is the topological mass generation mechanism? And what is its relation with the Higgs mechanism? Can we say that after the discovery of Higgs boson, the topological mass generation mechanism ...
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2answers
140 views

Weighing a flying bird [duplicate]

Let thing of a bird standing still in a box on top of a weighing machine that shows a mass $m_0$. Now, imagine that the bird is flying, still in the same box and the same weighing machine shows a mass ...
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0answers
73 views

Truck Mass & “4th power law”

Is it true that the damage caused to a road surface is proportional to the 4th power of vehicle axle weight, and if it is, what factors cause it to be related by a power of 4, or is it just the ...
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2answers
238 views

Does influence on gravity increase with mass when velocities approach the speed of light? [duplicate]

In other words, when a particle's mass increases significantly as it approaches the speed of light (c), does its influence on gravity increase, and if so, does it increase proportionally?
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2answers
997 views

If there is no gravity, does that mean there's no mass as well?

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
4
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2answers
697 views

What happens to a photon in a black hole?

Assume a photon enters the event horizon of a black hole. The gravity of the black hole will draw the photon into the singularity eventually. Doesn't the photon come to rest and therefore lose it's ...
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1answer
317 views

Why does mass in the universe have no limit in large size, but has a limit in small size?

We found VY Canis Majoris, a star so big it can't even be seen in scaled illustratations with the sun itself. However, we stop at particle physics, or quantum mechanics, i.e. particles, subatomic, ...
4
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1answer
209 views

Understanding the different kinds of mass in gravity

On this site, the Phys.SE question Is there a fundamental reason why gravitational mass is the same as inertial mass? has been asked. See also this Phys.SE question. The 'answer' provided on this ...
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0answers
4k views

What's the relationship between mass and time? [closed]

This question has arisen from a wish to understand an end-of-universe scenario: heat death. Are time and mass intrinsically linked? If so, does time "run slower" (whatever that may mean) in a ...
4
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1answer
175 views

Is $E=mc^2$ false?

Recently I have found a Youtube video saying that $$E=mc^2$$ is false. It is said that the real one is $$ E^2=m^2 c^4 + p^2 c^2 $$ where $E$=energy, $m$=mass, $c$=speed of light, $p$=momentum. Is ...
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1answer
186 views

Maxwell's equations as the particular case of massive vector field equation

There was a discussion (please look to the comments on my answer) about getting Maxwell's equations for free spin-1 field by using massive spin-1 representation's equations. I'll start from the ...
5
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3answers
349 views

Nobel Prize 2013: What is it about? [closed]

I would really like to understand Higgs-Englert’s discovery that earned them the 2013 physics Nobel prize. I tried reading their work, but understood nothing of it unfortunately. The reason why I’m ...
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2answers
137 views

Forces, Incline, and Mass

A farm tractor tows a $3900 kg$ trailer up a $16^\circ$ incline with a steady speed of $3.0 m/s$. What force does the tractor exert on the trailer? (Ignore friction.) I am having trouble ...
20
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7answers
3k views

Is (rest) mass quantized?

I learned today in class that photons and light are quantized. I also remember that electric charge is quantized as well. I was thinking about these implications, and I was wondering if (rest) mass ...
5
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5answers
7k views

What is Energy made of?

We have the famous equation $E = mc^2$, and we also believe that matter is made of particles. Then, What is the energy made of? If the two are interchangeable, there must be some common building ...
21
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8answers
2k views

Why is there a size limitation on animals?

Why is there a size limitation on human/animal growth? Assuming the technology exists for man to grow to 200 feet high, it's pretty much a given that the stress on the skeletal structure and joints ...
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2answers
184 views

Finally photons got a mass, what now? [closed]

Finally photons have got a mass, and what we have got is a new state of matter. Most of you must have heard about this till now, for those who don't, visit this page. I am not a pro or something, ...
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4answers
5k views

Why don’t photons interact with the Higgs field?

Why don’t photons interact with the Higgs field and hence remain massless?
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2answers
504 views

Does lightning have mass?

My chemistry teacher/book states that lightning is just light, and therefore has no mass and takes up no space (we're not very far through the book yet, it's defining matter). However, I take issue ...
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0answers
57 views

Agreggating the masses and coordinates of a number of points to calculate their gravitational pull on an object in a single step

I have $n$ points, each of these have a set of coordinates and a mass; what I want to do is calculate the resultant force they induce on an object whose coordinates I also know. I can do that simply ...