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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Mass-velocity-relation for tachyon

Suppose that $m = \gamma m_0$ with $$\gamma = \left(1-\frac{u^2}{c^2}\right)^{-\frac{1}{2}}$$ is valid for tachyons, where $m$ is the mass of the tachyon and $u$ its velocity. Since $u>c$, the rest ...
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0answers
49 views

How can spacetime affect massless entities? [duplicate]

Why is light affected and "bent" by spacetime if it has no mass or density?
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2answers
73 views

Why are the neutron and proton masses nearly equal? [duplicate]

The neutron to proton mass ratio is nearly one. Is there some fundamental reason from this or this simply a coincidence?
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2answers
328 views

Why are heavy things harder to lift?

According to multiple websites, any object in free-fall (no air resistance) on earth will accelerate towards the Earth at 9.8 m/s. If all objects fall towards the Earth at the same rate, regardless of ...
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1answer
95 views

How can we prove simply that acceleration for every freely falling body is equal to $g$? [duplicate]

If I allow two bodies of different masses to fall freely from same height towards the earth, how can I prove that the acceleration produced in both was constant and equal to gravity.
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2answers
76 views

Can mass be uncertain?

If you can have uncertainty in momentum, then wouldn't you have uncertainty in mass and velocity? Why can't mass be uncertain?
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2answers
65 views

How fast does an object have to be going to turn into energy [closed]

Albert Einstein's equation, $E=mc^2$, says that an object has to be going at the speed of light squared to turn into energy. How fast would this be in miles per hour?
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18 views

Why do we use $i\tau^2\Phi^*$ in standard model Yukawa terms? [duplicate]

If we for example only look at the first family of quarks, the Yukawa terms in the standard model are (ignoring the prefactors) $$ ...
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1answer
89 views

Mass spring system, elongation of the spring [closed]

Is it possible to calculate the elongation of a spring with only the length of the spring, a spring constant and the mass that is attached to the spring?
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46 views

What's wrong with this calculation of the center of mass of a triangle?

Find the center of mass $(x_G,y_G)$ of a homogeneous triangle of mass $m$. Divide it into infinitesimal rectangles of width $dy$, length $x$, mass $dm$ and area $dA$. We have $d A = x dy $ ...
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3answers
402 views

Can a cubic meter of space at absolute zero have any object with mass inside?

I ask this question because, I have seen many places where they say the average temperature of the universe is some 2 degrees K and this somehow relates to mass present within a given volume of space. ...
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1answer
80 views

What are the effects of increased mass on persons traveling at near light speed?

It's been a long time since I studied physics (and then only very superficially), so please bear with my gross naivete. This question's been running around in my head for about two weeks now, and I ...
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1answer
76 views

Relation between gauge symmetry and mass difference

Usually (like in Georgi's Lie Algebra book) people argue the reason why Gellmann $SU(3)$ flavor symmetry (u,d,s) can't extend to $SU(4)$ (u,d,c,s) or higher flavour symmetry is the their mass ...
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3answers
192 views

Uniqueness or multiplicity of ADM masses for spacetime manifolds with more than one “end”?

The question is: What is the mathematical and/or physical basis for saying that a (static) spacetime manifold with more than one asymptotically flat region at infinity ("end") has a distinct ...
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3answers
111 views

Finding the center of gravity of an object that does not have equal distribution of mass

NOTICE: I have very limited knowledge of physics so try not to confuse me, though I know it is inevitable. Say I have a grid of squares, where a □ has 1g of mass, while a ■ has 5g of mass. If I ...
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1answer
81 views

What is the total matter equivalent of the Sun's output per year?

Say we can collect all the energy from the sun's output and all the particles from the solar wind. If we had an energy to mass converter and turned everything into say, carbon, how many kilograms of ...
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2answers
142 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
40 views

Is anything without mass an EM wave?

For the longest time I thought the distinction between matter wave and other types of wave is the non-relativist mass of the "thing" under discussion. Photons are EM wave, electrons are matter waves. ...
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5answers
781 views

If you are on Earth, are your mass and weight the same?

I was wondering how mass and weight are different so I Googled it. I found that mass is constant no matter where you are because it is the amount of matter in an object and weight changes because it's ...
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2answers
58 views

Can center of mass move without any force?

For instance, consider a weight on one end of the ring. Assume that the ring has negligible mass compared to the weight. When the weight splits into two, moves around the ring and recombines at the ...
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0answers
43 views

How can a black hole increase mass? [duplicate]

As far as I know, the time dilation at the event horizon of a black hole is infinite, so everything falls asymptotically towards, but never reaching, the horizon for an outside observer. How then can ...
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0answers
98 views

Effective mass vs. cyclotron mass of carriers (e.g. in graphene)

Since my original question (below) didn't get any answers (maybe it's to specific?), I'd like to rephrase to make it more general. What is the relation between the effective mass and the cyclotron ...
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9answers
474 views

Why does my apple not weigh 500 tons?

Related to this question: What is potential energy truly? $E=mc^2$ - energy equals mass. So, if an object has gravitational potential energy relative to another object, it should have additional mass ...
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1answer
125 views

How to determine sign of coefficients in simple spring, damper, mass system?

For a system of the sort shown below: I have come to realize that I continuously make mistakes when it comes to determining the signs (or specifically the direction of the forces) of the ...
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5answers
2k views

Evidence that stationary masses in space actually attract each other

I'm finding it rather difficult to find experimental evidence that two stationary masses in space (unaffected by external massive bodies or gravities) actually attract one another. For moving masses, ...
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6answers
356 views

Mass without Matter?

My cursory studies of general relativity had introduced me to the concept of how gravity is associated with the warping of spacetime and that the presence of matter in space warps space and this ...
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17 views

Tight bounds between maximum weight and precision

Scales are rated according to their precision and maximum load -- attributes which seem to be universally close to one another (within about 3x10^4 grams). Eg, a scale that can measure up to a ...
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1answer
34 views

Measuring mass zero G [closed]

I work for a company that produces (among other things) a microbalance that can measure mass/weight from around 100ng to 100mg ie it is accurate over 6 orders of magnitude. However, this relies on ...
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3answers
120 views

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
32 views

Why are generally two of three effective masses identical?

In indirect semiconductors, the effective mass of electrons depend on the direction. There are three principle directions pointing away from the global energetic minimum in which the effective masses ...
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1answer
84 views

Higgs boson and gravity [closed]

I was reading earlier about how Higgs boson (aka The God Particle) is responsible for giving mass certain properties. Among these properties is gravity. What I'm wondering is, by studying Higgs boson, ...
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2answers
181 views

Can a superpartner be less massive than its SM counterpart?

Theoretically, can a superpartner be less massive than its standard model counterpart? I realize there are experimental constraints.
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1answer
112 views

Exoplanet Mass-Radius Diagram

I'm currently studying the following diagram: But I'm not entirely sure I understand what's going on. Is it just, that most exoplanets discovered, is pretty much made up of Hydrogen and Helium ? ...
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0answers
524 views

Weight of empty versus inflated balloon [duplicate]

Will the weight of a balloon filled with air be less than, greater than or the same as the same balloon after it has been deflated?
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2answers
240 views

Are all fermions massless at high temperatures?

According to the standard model, the electroweak symmetry is unbroken at high temperatures, and therefore all gauge bosons are massless then. But since fermions are said to acquire mass by a different ...
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2answers
96 views

Understanding variable mass equation for mass ablation/ejection

The "Variable-mass system" entry in Wikipedia, under the "Mass ablation/ejection" title, shows: $$p_2 = (m+dm)(v+dv) + u(-dm)$$ The parameter $p_2$ is for the momentum at $t+dt$, meaning $p_2 = ...
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2answers
728 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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1answer
313 views

How can magic be explained with Physics? [closed]

Assuming that, hypothetically, and for this example only, "magic" means things like magical powers. In movies, games, etc. we witness magic; however, it's never explained how it works with regards ...
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1answer
136 views

Questioning Einstein's view on gravity [duplicate]

Oke, so my mind is blown by Einsteins view on gravity, at least as far as I understand the basics and principles he based his views on. One of the first things that struck me was that most of his ...
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1answer
98 views

Center of mass finding question [closed]

Find the center of mass the rod in the figure if λ (the mass per unit lenght) varies with $x$ according to $\lambda=dm/dx=\beta x^2$, where $\beta$ is a constant. Sorry for quality of picture. I am ...
4
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1answer
305 views

What would happen if a negative mass crossed the event horizon of a black hole?

If negative mass really existed and somehow a very fast traveling negative mass object reached near the black hole's event horizon. What would happen when it crosses the event horizon? According to ...
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6answers
5k views

Is a block of cotton heavier than a block of iron?

if i have a block of cotton and a block of iron each containing a weight of 100 kg when measured on a weighing machine, in reality which one is heaver than the other, which one is heavier and why? ...
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2answers
45 views

Can Mass be found based on Volume?

I am trying to calculate the mass of an object given the volume of an object without knowing what it is made of. Is there a formula to find out something like this considering the object is on Earth ...
2
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1answer
123 views

What is the definition of density in a relativistic context?

In this question, there seems to be a clear presence of ambiguity, which raises the question: what is density in relativity? First of all, the question asks for the relativistic mass, "the apparent ...
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3answers
75 views

What should density of water be to keep box afloat?

I'm writing a platformer game and my physics engine is Box2D. I have successfully implemented buoyancy, but have a question about mass and density. My player is 80kg, a box has a density of 0.5 and ...
2
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1answer
42 views

Mass scaling in molecular dynamics

I've noticed some authors scale the mass of particles in molecular dynamics simulations while leaving the force field parameters the same in order to achieve materials of different densities. Does ...
17
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4answers
3k views

What's the difference between centre of mass & centre of gravity for massive bodies?

My book says: For most of the small objects, both are same. But for mammoth ones, they are really different ones. And in a gravity-less environment, COG is absent; COM still exists. Ok, what's ...
0
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1answer
191 views

What gives the higgs boson mass? [duplicate]

In light of the discovery of the Higgs boson. The Higgs Boson is a force particle which interacts with matter particles. My question is what does the Higgs Boson interact with to give itself mass.
2
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2answers
213 views

Understanding of the $m v^2/2$ formula for kinetic energy

I have some problem to intuitively understand why the kinetic energy grows quadratically with the velocity (at least in non-relativistic case). Assume the following experiment: we launch an unmanned ...
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1answer
100 views

What Is the Physics principle behind dropping a stone into a cup of water?

I have been doing an experiment about relationship between drop height of a stone and the loss of water in the cup it lands in. I found that after dropping the same stone into a cup with the same ...