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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Reduced mass and energy representation?

If we have a gravitational system where $m<<M$ then we can write down the energy of $m$ as follows: $$E=\frac{1}{2}m(\frac{dr}{dt})^2+\frac{L^2}{2mr^2}-\frac{GMm}{r}$$ but if $m$ is not small ...
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76 views

What does the mass of a quark mean?

The mass of an electron includes the mass of the electric field it creates. If electrons have a radius, it's known to be small enough that the mass of the electric field would be more than the total ...
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14 views

Does mass increase at relativistic OUTSIDE of the mass's frame of reference? [duplicate]

There are other questions on here with responses saying that the mass does not change from its own frame of reference. But those answers were somewhat unclear if the mass changes to someone observing. ...
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82 views

Is it (theretically) possible to reduce inertial mass without reducing matter quantity? [closed]

Ok, please bear with me because I only have a very little (or no?) understanding of physics outside Newtonian laws... So I was playing a video game called "Mass Effect" in which a particular compound ...
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62 views

That the gravitational mass equals to inertial mass can imply that only Einstein-Hilbert action is satisfied

I read Spacetime and Geometry by Sean Carroll. In p. 166 there is a comment that GR's action is nonlinear because if it is linear like the EM field, then graviton will not interact with each other, ...
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91 views

Effects of travel greater than speed of light [closed]

What will happen if a person with say weight of 100 kilograms, starts to travel with, a) equal to speed of light? b) greater than speed of light?
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307 views

How do we know that photons are exactly massless and travel exactly with speed $c$ in vacuum?

I know that this question may sound stupid, but what I mean is that photons have some energy and no mass, yet the mass and energy are said to be equivalent (or maybe I got that part wrong). In an ...
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2answers
306 views

Does “Infinite Universe” Imply Infinite Mass?

In accordance with the FLRW Metric with a curverature of $k=0$ (as observationally supported by several of NASA's experiments including WMAP, Planck satellite, DASI, etc.) the universe is spatially ...
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214 views

Mass, Acceleration, and Force

The Problem: (a) A car of mass m is on an icy driveway inclined at an angle of 20$^{\circ}$, Determine the acceleration of the car, assuming that the incline is frictionless. The questions is ...
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136 views

Why won't a block less dense than water fully submerge?

Suppose we have an object of volume $1\: \mathrm{m^3}$. Mass of that object is $500\: \mathrm{kg}$, which means that the density of the object is $500\: \mathrm{kg/m^3}$. If the object is in water it ...
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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? ...
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Does a black hole have any kind of mass?

Currently in my academics I am studying about the Gravitation. In the chapter I came across a term called the Escape Velocity (It's the velocity of any celestial body which is required by an object to ...
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66 views

Explicit Symmetry Breaking: Where do the additional d.o.f. come from?

Massless vector bosons have only two independent degrees of freedom, while massive ones have three. In spontaneous symmetry breaking, the massless vector belonging to the broken group becomes massive ...
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223 views

How much does the Earth's population affect the force of gravity? [duplicate]

If everyone on earth except one person were to gather up in one location, say the North Pole, and jump at the exact same time and stay airborne for about 1.5 sec. And that one person who did not jump ...
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5answers
158 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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78 views

Should chemists at different altitudes factor in the specific gravity value when measuring mass via spring scale?

Forgive my ignorance but I've never found an answer to this question....In the spirit of independent confirmation/research replication, should chemists operating a different altitudes above sea level ...
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4answers
162 views

A question on force and acceleration

Q 1. Two bodies, $m_1$ and $m_2$, in contact with each other, are under constant acceleration $a$ in the same direction. Find the force exerted by $m_1$ on $m_2$. A similar question with my ...
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1answer
91 views

The Force Required To Move An Object Which Has Unequal Mass Distribution

Suppose I have an object, let's say a stick which is of length, let's say 1 meters. I have most of the mass of the stick concentrated on one side of the stick (the center of mass). Now, if I move the ...
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38 views

Alpha Particles Moving Object

I'd like to apologize in advance because this may be a silly/obvious question, but could alpha particles theoretically move an object? My basic idea is that alpha particles could cause an object to ...
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1answer
56 views

How would behave theoretical matter with negative mass? [duplicate]

I wonder if there is any possibility to evaluate theoretical characteristics of matter with negative mass? This is not thing of anti-mass but classical matter just with negated weight. I thing that if ...
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1answer
159 views

Follow up question regarding: Deceleration rate of objects of different mass but the same otherwise

My first question was answered here: Deceleration rate of objects of different mass but the same otherwise . But based on that, here is a follow-up question (I also edited my first post with the ...
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2answers
62 views

When talking about atomic mass, how is $E=mc^2$ factored in? [duplicate]

When talking about atomic mass in the periodic table of elements, is this number the mass of the element at rest? If I understand correctly, the (relativistic) mass of an element will increase as the ...
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4answers
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Why do objects fall at the same acceleration?

I read these two posts and now I am more confused. Do heavier objects fall faster? Don't heavier objects actually fall faster because they exert their own gravity? I was going to ask: if mass ...
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1answer
34 views

two bodies are travelling with equal acceleration

two bodies are travelling with equal acceleration in the same direction and are in contact with each other. What will the force exerted by 1st body on second be? By taking an example of masses 5 and ...
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1answer
51 views

Radiative mass generation in QED?

Does self-energy correction leading to a modification in the mass of the electron can be called radiative mass generation? In Zee model of radiative neutrino mass generation, the helicity of the ...
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1answer
59 views

Can we define the effective mass or the moving mass of a photon?

I know that the rest mass of a photon is zero. but the photon can be bent by gravity (which can also be explained by the curvature of space-time due to the effect of mass), this implies that it must ...
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What's the difference between the five masses: inertial mass, gravitational mass, rest mass, invariant mass and relativistic mass?

I have learned in my physics classes about five different types of masses and I am confused about the differences between them. What's the difference between the five masses: inertial mass, ...
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Why should it be allowed to set the einbein to unity?

The Polyakov action for a massive free point particle with worldline $\gamma$ is given by $$ S[\gamma] = \frac{1}{2}\int_\gamma e \biggl(\frac{1}{e^2}\dot{x}^2 - m^2\biggr)\mathrm{d}\tau $$ where ...
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148 views

When a body accelerates, it gains (relativistic) mass; after stopping, is the (relativistic) mass different from before it started accelerating?

When a body accelerates, it gains (relativistic) mass $m$ according to the relation $$m=\frac{m_0}{\sqrt{1-(v/c)^2}},$$ where $m_0$ is the (rest) mass. But after it stops is the gained (relativistic) ...
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417 views

What part does the Higgs boson play in conveying mass?

I am a high school physics teacher and did my physics degree a while ago, well before the Higgs boson was on in the physics undergraduate syllabus. Now, I am a little confused. The recent discovery ...
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23 views

What does one get when admitting negative mass? [duplicate]

So essentially, both gravitational and electric fields behave in exactly the same way. The only difference is that, while mass can only be positive, charge can be positive or negative. As I understand ...
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88 views

Confused about gravitational potential energy [duplicate]

So learning the concept of gravitational potential energy, my professor says that when lifting an object without any acceleration, the force we exert on the object to lift it is the same as the force ...
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115 views

When referring to weights and mass of weights in a physics laboratory, do we use the term mass or weights?

What terminology is used to refer to weights/ mass/ weight of mass/ mass of weights when referring to the mass of weights in a physics report? My question is more of the weights that we use in the ...
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374 views

For a massless pulley moving upwards with acceleration, is the upward force equal to the downward force?

Imagine a massless and frictionless pulley with two weights hanging either side of the pulley by a massless string. Like this except not attached to a ceiling Rather than being fixed to a ceiling, ...
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1answer
53 views

Why does gravity enact force? [closed]

Gravity would cause two objects in a vacuum to move toward each other. I understand that gravity is a force that exists as a product of energy's original conversion into mass and the continuing change ...
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Is my interpretation of how a gravitational wave is formed correct?

I'm sure many here are familiar with the following image showing the 2D representation of how the fabric of spacetime is warped by the presence of mass:- Can this fabric be interpreted as an ...
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Why do two bodies of different masses fall at the same rate (in the absence of air resistance)?

I'm far from being a physics expert and figured this would be a good place to ask a beginner question that has been confusing me for some time. According to Galileo, two bodies of different masses, ...
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2answers
310 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
133 views

Gravitational interactions by energy or by mass?

The mass-energy equivalence, first established by Einstein is an important and highly discussed phenomenon in physics. Without claiming much knowledge about high-end discussions on this topic, I would ...
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1answer
422 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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3answers
726 views

While finding escape velocity, does human mass counts as the mass of Earth?

Escape velocity depends upon the mass of earth. my doubt is whether human mass adds into it or not? If it add then Earth's escape velocity would be increasing!
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If protons and electrons had similar masses

If electrons and protons had the same mass, would they still be in a stable orbit around their barycenter, or would they eventually collide? Similarly, a positronium(or protonium) only lasts extremely ...
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4answers
3k views

Why does a semiconductor hole have a mass?

I have read that holes in semiconductor are nothing but vacancies created by electrons. But how can this vacancy i.e. hole has a mass?
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2answers
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Why do electrons orbit protons? [duplicate]

I was wondering why electrons orbited protons rather than protons orbiting electrons. My first thought was that it was due to the small amount of gravitational attraction between them that would ...
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663 views

How do you estimate the mass of a star?

How do we estimate the mass of a single star? I guess we need the luminosity the surface temperature, radius, distance, etc. But we know nothing about the reality, because we can measure the real ...
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2answers
339 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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Is there a difference between the speed of light and that of a photon?

As in the title I am curious whether there is a difference between the speed of photon and the speed of light, and if there is what is the cause of such a difference?
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222 views

If rest mass does not change with $v$ then why is infinite energy required to accelerate an object to the speed of light?

I know that as the velocity increases, the mass of the object also increases so it becomes tougher and tougher to move the object which ultimately leads to a requirement of infinite energy to ...
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188 views

Intuitive explanation of how hadron mass emerges from the strong force

I'm not familiar with QCD, but I'm looking for intuitive explanation of this phenomenon (it could be that easy explanation does not exist). What I've read is that large part of hadron masses arises ...
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Mass of empty AdS$_5$

Five dimensional empty AdS$_5$ space has mass $$ E = \frac{3 \pi \ell^2}{32 G}. $$ Is the above equation correct? Let's do some dimensional analysis to confirm. In natural units, in 5 dimensions ...