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.

learn more… | top users | synonyms

2
votes
1answer
92 views

What is the center of Earth's landmass?

I have read, several times, that the Great Pyramid is located at "the center of Earth's landmass". How do we define "Earth's landmass"? And once defined, how do we find the center of it?
3
votes
2answers
177 views

Does “Crack The Whip” actually speed you up?

"Crack The Whip" is a game played on ice skating rinks where several individuals line up all facing the opposite end of the rink, and skate forward. When the group reaches the opposite end of the ...
0
votes
1answer
288 views

effect of object mass in coeficient of restitution

I know the coefficient of restitution depends on the velocity before and after the impact of a bouncing ball. How does the mass affect it. Can't figure it out. v ...
0
votes
2answers
123 views

Time Delays in General Relativity

If gravity propagates at, or less than, the speed of light, and is therefore not instantaneous, does that introduce time delays to gravity? For example: suppose that we, the observer, sit within the ...
2
votes
1answer
433 views

Fermion mass Higgs mechanism

How get fermion like a electron a mass through the higgs-mechanism? Can someone explain me this with formulas (Lagrangian)? I know that the Yukawa interaction has something to do with, is that right? ...
0
votes
2answers
116 views

Why can't I calculate center of mass via torque? Results off by a few percent

Why do I keep getting a slightly different result from the following two ways of determining the center of mass of a rigid, geometrically simple object? The object is a rectangular 5(x) by 7(y) ...
-1
votes
1answer
80 views

Relativistic momentum and mass [duplicate]

Is there even a relativistic mass or just relativistic momentum? How does one reason to prefer one over another? What is the problem with saying a hot gas will have more mass/inertia to it?
2
votes
2answers
119 views

When “weight” of an object is listed, is it really the mass or the weight?

I Have read an earlier post regarding this, but the answer wasn't perfect enough or I didn't understand so! Let me put it to clear, I know difference between weight and mass. Also I know the ...
3
votes
2answers
221 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 ...
3
votes
1answer
137 views

Does corrosion of iron increase its mass?

Does corrosion of a sample of iron increases or decreases its mass? I think that the mass will increase because of additional oxygen atoms.
2
votes
3answers
177 views

How can the Lorentz transformation cause two objects' masses to both increase?

Suppose there are two people A and B. A is standing on the earth and B is on a rocket in space. Now B passes by the earth at a speed of 0.9c and A sees him. According to A, B's mass would have ...
3
votes
0answers
141 views

Reducing massive representation of the Poincare group to the massless one

I want to ask about the connection for massive and massless representation of the Poincare group. Sorry for the awkwardness. First I must to represent the formalism for both of cases. Massive ...
1
vote
2answers
575 views

Polarization vectors of massive and massless particles

I read from Mandl & Shaw that when quantizing massless vector particles such as photons in Lorentz gauge, there are 4 linearly independent polarization vectors (2 of them being able to "gauged ...
2
votes
1answer
75 views

Neutrino mass and energy question

If a neutrino has mass then it travels less than the speed of light. Suppose I boost myself to the rest frame; i.e. bring it to rest in the laboratory. Now if it oscillates between different states ...
2
votes
2answers
215 views

Increase in Mass with Velocity [duplicate]

I just had a confusion. Does the mass of the body actually increase when it is moving with a certain velocity? Or does it only look like the mass has increase to another observer. How can the actual ...
-1
votes
1answer
342 views

Measure mass difference of an object without a scale

For a project i need to separate items based on their mass in real time. I like to explore measuring weight of an object (round metal ball) by taking photographs (several) during free fall and ...
1
vote
2answers
382 views

Conservation of mass energy and kinetic energy in different reference frames

With a little work it's easy to show that kinetic energy by itself is not necessarily preserved when switching between frames of reference. And it is my understanding that energy should be preserved ...
2
votes
1answer
206 views

Pauli-Fierz “massive” equation and linearized gravity

It it known that the massive spin-2 irreducible representation of the Poincare group is the traceless symmetrical transverse 4-tensor $h_{\mu \nu}$ with rank 2: $$ (\partial^{2} + m^{2})h_{\mu \nu} = ...
37
votes
6answers
2k views

What keeps mass from turning into energy?

I understand the energy and mass can change back and forth according to Einstein. It is fluid; it can go from one to the other. So, what keeps mass from just turning into energy? Is there some force ...
2
votes
1answer
391 views

What are mass eigenstates?

According to Wikipedia Neutrino oscillation arises from a mixture between the flavor and mass eigenstates of neutrinos. That is, the three neutrino states that interact with the charged leptons in ...
1
vote
1answer
64 views

Stacking Shelves with Overhang

I want to stack some boxes which are 14" x 10" with some 12" records inside. This means that there will be a 2" overhang outside of each box. I know that to have an item to balance on a edge 50% of ...
6
votes
4answers
2k views

Do all massless particles (e.g. photon, graviton, gluon) necessarily have the same speed $c$?

I suppose there was a discussion already on speed-of-gravity-and-speed-of-light. But I silly wonder whether all the massless mediators of four fundamental forces, i.e. Graviton: $g_{\mu\nu}$ ...
0
votes
1answer
75 views

Is there a minimum mass is required for light to be noticeably bent?

The sun bends the trajectory of light slightly. And a black hole will bend the trajectory entirely. This is all dependent on the proximity to the source of gravity. For a given angle, is there some ...
1
vote
1answer
148 views

Are there any good references on the “gravitational” curvature of spacetime of a moving mass being distorted due to special relativity?

In this Wikipedia paragraph suggesting an explanation for the phenomenon of inertia, it claims: Another physicist, Vern Smalley, has derived the Lorentz transformation for mass by assuming that ...
3
votes
1answer
286 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 ...
0
votes
2answers
152 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 ...
1
vote
1answer
108 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 ...
1
vote
2answers
47 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?
1
vote
1answer
120 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 ...
1
vote
2answers
434 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 ...
0
votes
1answer
109 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, ...
15
votes
6answers
917 views

Does the weight of an hourglass change when sands are falling inside?

An hourglass H weighs h. When it's placed on a scale with all the sand rested in the lower portion, the scale reads weight x where x = h. Now, if you turn the hourglass upside down to let the sand ...
2
votes
2answers
491 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 ...
4
votes
1answer
154 views

Effective mass of a black hole?

Suppose a black hole forms from a given mass of particles such as the core of a star going supernova. The black hole formed will have an effective mass due to the curvature of space time induced. Such ...
1
vote
2answers
481 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?
4
votes
2answers
178 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 ...
1
vote
1answer
109 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 ...
0
votes
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?
0
votes
0answers
90 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 ...
1
vote
1answer
133 views

Changing effective mass to lower frequency

I'm trying to scale a physical object up in size, either double or quadruple. It's a circular acrylic plate, with multiple weights attached around it's edge, to lower the resonant frequency to a ...
8
votes
1answer
287 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? ...
2
votes
2answers
197 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 ...
0
votes
1answer
223 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
votes
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, ...
13
votes
1answer
440 views

Is it only the Higgs field that stops me from getting to $c$?

Is it only the higgs field that stops me from accelerating up to the speed of light or is there other restriction concerning the increase in mass? In other words if I had a Higgs field shield on my ...
2
votes
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 ...
3
votes
1answer
226 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 ...
1
vote
1answer
58 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?
-2
votes
1answer
230 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?
0
votes
2answers
122 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 ...