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.
1
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1answer
431 views
Is the curvature of space around mass independent of gravity?
Is the curvature of space caused by the local density of the energy in that area?Could gravity be a separate phenomenon only arising from the curvature of space? For instance if the density of energy ...
3
votes
1answer
265 views
Effects of parallel superconducting plates
Assuming the existence of virtual particle field ( zero point energy field) Casimir force is produced by 2 parallel conducting plates excluding some of the frequencies between the plates, if these 2 ...
3
votes
1answer
382 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 ...
3
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2answers
64 views
How long does it take to weigh an uncooperative mass?
(This is curiosity, not a practical question. It was inspired by standing still for a digital scale, and considering whether it would be possible to make a scale that could handle being jumped on, ...
2
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1answer
205 views
What is the mass of a photon in non-empty spaces?
It is a well known result of the special theory of relativity that the photon has no rest mass, because for a particle to attain the speed of light, it must have zero rest-mass. I will not dig into ...
0
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2answers
200 views
How far does physics influence russian roulette?
Prompted by this discussion on the math exchange
My thought was that the added mass of a bullet in an otherwise empty revolver would bias the chamber spin such that the bullet would remain in one of ...
2
votes
1answer
104 views
Can non-free forces change the rest mass?
While reading Hobsen et al.'s "General Relativity: An Introduction for Physicists", I came across a bit confusing derivation. Multiplying the 4-force and 4-velocity, the following derivation can be ...
2
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2answers
302 views
Does the measured mass of earth include that of the atmosphere?
Just what the title states please... and perhaps naive too...
Wikipedia pegs the mass of our Earth at 5.9722 × 10^24 kg.
Does this figure include the mass of the Atmosphere?
2
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2answers
521 views
How could something have negative mass?
With all the theories on how Neutrinos apparently broke the light barrier, there was one theory someone told me of how neutrinos might have less than zero mass, but she didn't explain how this was ...
1
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1answer
374 views
If photons are deflected by a strong gravitational field, then how come photons do not have mass? [duplicate]
Possible Duplicate:
Explain how (or if) a box full of photons would weigh more due to massless photons
It has been proved and showed through experiments that light can be bent by the Sun or ...
2
votes
1answer
165 views
Motion is relative, right? And most pop sci relativity explanations are somewhat incorrect?
On page 20 of A Brief History of Time:
. . . all observers should measure the same speed of light, no matter
how fast they are moving.
But in an observer's frame of reference, they're actually ...
4
votes
1answer
148 views
Is there a theory which treats particles as classical point singularities?
Is there a published theory that looks at all matter as occupying no space and only being felt because of its gravitational pull?
We've been taught in school that matter has mass and occupies space. ...
3
votes
4answers
582 views
What if we could give photons some mass?
I was reading an article and these paragraphs got me wondering...
Before I list the replies, here is some background. The Higgs mechanism describes an invisible field that, it is argued, split one
...
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3answers
207 views
Formation of black holes
If stars start with a finite density and light can escape from them, how can they be compacted to form a mass with infinite density which light cannot escape? The black hole will have the same mass as ...
4
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0answers
23 views
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 ...
9
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2answers
245 views
Do we have an idea about the amount of matter in the universe?
Do we consider the amount of matter in the universe to be "infinite"? Or do we have an idea about "how much" there is?
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1answer
791 views
Vertical component of moving weight at a 45 degree angle
Here's an easier one.
I use the leg press machine at the gym so I don't have to worrying about hurting myself while lifting heavier weight.
The weight glides on a track that looks to be 45 degrees.
...
1
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2answers
528 views
Calculating the gravitational acceleration inside of a planet
Plant X has a radius of 5000 km and is composed of two layers.
The first inner layer ranges from the centre to 2000 km from centre, it's density is 8 kg / dm^3.
The second layer ranges from 2000 ...
2
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2answers
126 views
Inertial Mass of a scalar field
Does it make sense to talk of the inertial mass of a scalar field? By the equivalence principle, it must be equal to its gravitational mass. We know that the scalar field contributes towards the ...
3
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3answers
861 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 ...
3
votes
1answer
134 views
Difference between baryonic, inertial and gravitational mass? (and relation to dark matter)
Inertial mass: determined from Newton's f = ma
Gravitational mass: determined via Newton's law of gravity
Baryonic mass: sum of mass of all baryons.
Which ones ...
4
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1answer
155 views
Avogadro's number
Could I get an explanation of Avogadro's number and how it relates to determining the mass of a substance? My chemistry textbook only serves to confuse me and the Wikipedia article is aimed towards a ...
3
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5answers
588 views
Does $E$ really equal $mc^2$?
I'm currently in a debate with a co-worker.
If mass is sped up to the speed of light, does the mass become energy?
3
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1answer
312 views
Equation that tells me the rpm and mass of a spinning disk needed to keep a second large mass stable using gyroscopic effects
I am trying to figure out how large of a mass and how quickly I need to spin said mass to keep a two-wheeled robot stable. Ideally, I am looking for a formula that relates m1=mass of robot, m2=mass of ...
3
votes
2answers
601 views
Why do neutrino oscillations imply nonzero neutrino masses?
Neutrinos can pass from one family to another (that is, change in taste) in a process known as neutrino oscillation. The oscillation between the different families occurs randomly, and the likelihood ...
0
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1answer
558 views
How do Einstein’s equations support mass gain in particle accelerators? [duplicate]
Possible Duplicate:
Why does the mass of an object increase when its speed approaches that of light?
A charged particle that is accelerated through a particle accelerator like CERN ...
0
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0answers
83 views
Masses of all the particles in the Standard Theory [duplicate]
Possible Duplicate:
If photons have no mass, how can they have momentum?
I'm sure this question has been asked here before but I wasn't able to find it clearly answered in one q/a session. ...
2
votes
6answers
2k 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 ...
1
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1answer
160 views
Measuring the mass using angular velocities
I have 2 objects which are intially connected together, $O_1$ and $O_2$. When they are connected together, they have a rotation rate about their center of mass of $w_1$. $O_2$ is cleanly released from ...
3
votes
2answers
188 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?
3
votes
2answers
555 views
Does a photon see a 0-D universe?
For a massless particle the spacetime interval between its point of emission and point of absorption is zero: the two points coincide. From the vantage point of such a particle space-time has reduced ...
1
vote
1answer
252 views
Where are the centers of mass for a baseball bat vs. a cricket bat?
My friend and I were comparing the rightness of a cricket bat versus a baseball bat for general violence purposes. (Eg, rioting.)
Where are the centers of mass for these two instruments? Which would ...
1
vote
4answers
676 views
Is the earth expanding?
I recently saw this video on youtube:
http://www.youtube.com/watch?v=oJfBSc6e7QQ
and I don't know what to make of it. It seems as if the theory has enough evidence to be correct but where would all ...
4
votes
2answers
249 views
How to calculate the highest theoretical artificial hill?
The biggest peak in the world is Mount Everest.
Imagine someone starting to make an artificial hill (like pyramide) from soil (earth).
So, when starting with an 200x200 Km base area, with 45degree ...
10
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3answers
762 views
Decay of massless particles
We don't normally consider the possibility that massless particles could undergo radioactive decay. There are elementary arguments that make it sound implausible. (A bunch of the following is ...
3
votes
2answers
382 views
How Can We Measure The Mass Of Particle?
As we know, the mass of well known particles are below.
$m_{n}\approx0.0000000000000000000000000016749286[kg]$
$m_{p}\approx0.0000000000000000000000000016726231[kg]$
...
1
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1answer
192 views
Mass of a galaxy via Luminosity [closed]
Is there a way of calculating the mass of a galaxy, or even a nebula from the luminosity?
EDIT
I'm deleting this, and moving the question to Astronomy Stack Exchange - thanks david
2
votes
1answer
293 views
Does magnetised material lose weight?
I've had argument on a forum about this. People think, that:
if the same object is magnetised, it has less energy. so by $E = mc^2$ it weighs less than an object that is not magnetised (hence spin of ...
4
votes
4answers
214 views
Massive particles and speed of their propagation
Can one show that in quantum field theory at least some example massive particles propagate with speed less than speed of light, while massless travel at speed of light? Well, motion is a different ...
12
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3answers
3k views
How do we determine the mass of a black hole?
Since by definition we cannot observe black holes directly, how do astronomers determine the mass of a black hole?
What observational techniques are there that would allow us to determine a black ...
11
votes
4answers
864 views
Why does a black hole have a finite mass?
I mean besides the obvious "it has to have finite mass or it would suck up the universe." A singularity is a dimensionless point in space with infinite density, if I'm not mistaken. If something is ...
2
votes
2answers
335 views
Mass in terms of energy
Given the relationships between mass and energy in relativity, and given that particles with mass can be created given energy over the threshold energy, and vice-versa, can we say that mass is simply ...
-2
votes
1answer
185 views
future light cones and light paths
I understand that an event, in a four dimensional space-time, produces a light cone. As time increases the cones gets larger on either side of the event (past and future). For example the if the sun ...
5
votes
3answers
286 views
bound states of massless fields?
Question: are they mathematically possible at all? physically?
with finite mass systems, usually the binding energy contributes to the rest-mass of the system. It would seem that even if you could ...
5
votes
4answers
813 views
Atomic mass of Copper-63?
This URL lists the mass of Copper-63 as 62.9295975(6) and this other URL lists the mass as 62.939598. These values differ by almost exactly 0.01 which seems hard to explain by experimental error. ...
0
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0answers
136 views
Spinning X-Rays [closed]
X-Ray jets emit from galaxies as a result of spinning mass.
I'm thinking about the ties between electricity and magnetism here, and how Gauss law ties all this stuff together.
OK, so is there a way ...
0
votes
2answers
2k views
Does an Increase of Force affect the Speed of an object if the acceleration stays constant?
If I had a mass of $100\:\rm{kg}$ accelerating due to gravity, using $F=ma$:
$F = 100\:\rm{kg} \times 9.8\:\rm{m/s^2}$
$F = 980 \:\rm N$...
If I increased the mass to 200kg, the force would be 1960 ...
3
votes
6answers
1k views
6
votes
1answer
457 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?
8
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3answers
3k views
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,
...
