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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532 views
Why does an object with higher speed gain more (relativistic) mass?
Today, in my high school physics class, we had an introductory class on electromagnetism. My teacher explained at some point that an object with a very high speed (he said it started to get somewhat ...
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5answers
977 views
Why Gravity attracts all objects with the same speed?
Why Gravity attracts all objects with the same speed? Is this question was solved? What is the exact answer?
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1answer
227 views
momentum conservation question involving a rocket and a spaceship [closed]
With the engines off a space ship is cruising at a velocity of 230m.s
It fires a rocket straight ahead at the enememy vessel. The mass of the rocket is 1300kg and the mas of the ship (not including ...
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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 ...
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0answers
114 views
Do all the particles acquire mass in the Standard Model due to the Higgs mechanism only?
I know that a mass term for an intermediate boson is not compatible with the gauge symmetry. But in principle a mass term for the electron field does not violate a gauge symmetry. However to build an ...
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2answers
463 views
How do you weigh a box on a scale whose limit is too low?
As you will see I know nothing about physics and after being asked to solve a physics problem in a recent interview wanted to ask it of professionals and see what the response would be:
I have a set ...
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5answers
370 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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4answers
416 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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2answers
423 views
Free fall of two spheres made of same materials, different masses, with air resistance
Two people falling with the same parachute will gain different speeds if their masses are different. The upward air drag will needed to be bigger for a heavier person, since gravitational force is ...
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3answers
236 views
What does “nearly infinite mass” mean?
I am sure this is a silly question, but I was reading something that described the pre big-bang universe as having "nearly infinite mass."
How can something be "nearly" infinite? The term seems to ...
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2answers
109 views
What is mass of free up and down Quark?
Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nuclei. Due to a phenomenon known as color confinement, quarks ...
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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 ...
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2answers
88 views
Do photons have mass? [duplicate]
As a student in a highschool physics class, my teacher has repeatedly told me that photons are massless. Yet, I have also heard from other sources that photons have momentum. If photons were to have ...
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3answers
147 views
What truly is mass, and is there a direct way to measure it?
We know a mass of an object of one kilogram as an object that weighs W = mg = 9.8 N and we reference it to that, (when it should as a fundamental parameter describe weight not the opposite). But if we ...
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2answers
162 views
Why does the (relativistic) mass change & why?
I studied that when an object moves with a velocity comparable to the velocity of light the (relativistic) mass changes...but I am really eager to know how does this alteration take place....If anyone ...
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3answers
468 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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4answers
581 views
Does matter with negative mass exist?
Or does it exist mathematically?
Is it really inconsistent with a common-sense, mathematics or known physical laws?
As far as I understand, if it exists, it must be far away from the "positive" ...
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2answers
131 views
The physics behind The Great Flood [closed]
The book of Genesis floats (pardon the pun) some interesting numbers when discussing the Great Flood. For example, it rained for 40 days and 40 nights, and at the end of that time, the entire planet ...
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2answers
130 views
Do particles gain mass only at energy levels found during the big bang?
I am trying to make sure my understanding is correct.
At energies and temperatures found during the big bang (or at CERN recently), the Higgs mechanism comes into effect. When it does, there is a ...
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1answer
115 views
Why does Lorentz factor not hold for relativistic mass when we apply it to photons? [duplicate]
We know that the photon itself is massless particle $m_0=0$. But we also know, that the mass of the objects does increase with their energy. And we know that under certain circumstances (gravity, ...
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1answer
103 views
Does gravitational force attract bodies with mass or with energy?
On my textbook is written that gravitational force is the force that attracts bodies with mass. But I've seen on a book that It actually attracts bodies with energy. I'm having a class tomorrow and I ...
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1answer
156 views
How much force is required to lift the back of a 2,480 lb car in the air from the bumper?
I don't know the EXACT measurements, but I can closely guess that the bumper is about 18 inches from the ground, and the engine is in the front, yes(the engine is about 20 inches from the front bumper ...
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1answer
171 views
Does the increase of (relativistic) mass, while flying near speed of light, has any impact on astronauts? [duplicate]
Possible Duplicate:
Would travelling at relativistic speeds have any impact on human biology?
I am asking myself this question for a few day. What is the answer on: Does the increase of ...
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1answer
89 views
Does mass concentration affect the torque induced by a force?
If you had two bodies with the same weight but one having mass concentrated more in the center, while the other had most mass concentrated on the outside, but both had the same center of mass and ...
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1answer
120 views
What is the definition of density as a function?
(Before I start, I don't know which tag is suitable for this post. Please retag my post if it bothers you.)
Let's say there is a string on $[0,1]$ with a mass given by $m(x)$. ($m(x)$ means the mass ...
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3answers
307 views
If something weighs 25 kg, how do I find the mass of the object?
An object is falling and it weighs 25 kg (on a scale, presumably). What is its mass?
I know that weight is measured in Newtons and mass in kilograms, but what if a problem states that something ...
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1answer
184 views
What gives matter Gravitational Mass? [duplicate]
Possible Duplicate:
Does the equivalence between inertial and gravitational mass imply anything about the Higgs mechanism?
In Higgs mechanism, Higgs field, which likes syrup, slows down ...
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1answer
619 views
Calculate mass of air in a tyre from pressure
How can one calculate the mass of air inside a tyre, given a particular tyre size; a pressure, in $kPa = \frac{1000kg}{m\cdot s^2}$; and assuming room temperature, and normal air composition? I can't ...
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1answer
170 views
Why not accurate masses of elementary particles?
In the standard model of particle accuracy in calculating mass is very low.
And you can not predict the upper limit of Higgs particle mass accurately. Why not accurate masses of elementary particles?
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4answers
677 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 ...
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2answers
103 views
Do photons actually generate a slight kinetic force?
My question is even though photons have no (rest) mass, do they emit a external force due to EM radiation causing electrons to be excited and jump to higher energy shells which electrons have mass ...
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1answer
99 views
Is light affect by gravity? Why?
I would like to know if light is affected by gravity, also, I would like to know what is the more correct for the definition of gravity: A force that attracts bodies with mass or force that attracts ...
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3answers
112 views
Does Earth's rotation change at a constant rate?
Follow-up to
Is Earth's orbit altered by recoil from take-off/launch/recovery of aero/space vehicles? and
How much meteoric/space dust does the moon accumulate daily?
Is the length of the day ...
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1answer
139 views
Is $w=mg$ the right way to calculate mass?
How can you find the mass of an object by using a weight and a gravitational acceleration from another planet then earth? I was given $5.8\text{ N}$ and an acceleration of $4.0\ \mathrm{m/s^2}$. The ...
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1answer
116 views
How do the energy eigenvalues of rotational degrees of freedom in statistical mechanics come about?
I want to understand the hierarchy different degrees of freedom of a mechanical system. Specifically, I want to understand which subsystems equibrilate faster and why. This question comes up:
Why ...
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2answers
245 views
Why do photons add mass to a black hole?
Why do photons add mass to a black hole?
When photons are taken irreversibly into a black hole does the mass of the BH increase?
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1answer
92 views
Are there any well-known theories successfully unifying the inertial and gravitational mass?
From what little I know of general relativity, the equality of inertial and gravitational mass is an axiom of the theory. I suspect that this precludes GR from unifying them in the same sense as ...
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3answers
108 views
Carrying water on person, or on the frame when bicycling
So, the question is as follows:
What is the difference in work exerted by the rider in the two following scenarios?
a) Rider + bike. Water carried in a holder on the frame
b) Rider + bike. Water ...
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1answer
224 views
How does a star wobble due to orbiting bodies
What equations determine how a star wobbles in response to an orbiting planet, and can it be used to determine the mass of distant objects based on the wobble?
If there are other more reliable ...
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2answers
316 views
At what point does a projectile leave a slingshot?
Assuming a frictionless / "perfect" environment, and given a ball held in an elastic sling (like a hand-held catapult) where the pocket is lighter than the projectile itself, what is the point at ...
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1answer
266 views
Calculating the force of a mass bearing down on an object
I need to calculate the force of a weight bearing down on a smaller object, constraining it from expansion.
The weight bearing down has a much bigger surface area than the smaller object.
I know the ...
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2answers
530 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 ...
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1answer
194 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
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1answer
53 views
Defining the star as the ellipse focus rather than the barycenter, what does the other focus do? [duplicate]
There are a lot of images and animations on the internet depicting two bodies orbiting around their common barycenter. The barycenter is defined as the (let's say right) focus of the ellipse.
If we ...
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1answer
53 views
A sphere, a simple object?
In this video, the woman says that a sphere is a pretty simple object. What intrigues me is the use of a sphere for such a calculation. First of all, the sphere wouldn't be perfect as a perfect sphere ...
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1answer
194 views
Gravity and free fall
In Wikipedia it's stated that "[..] gravity, is the natural phenomenon by which physical bodies appear to attract each other with a force proportional to their masses".
Then I found many examples ...
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1answer
107 views
Photons and Relativity
Consider a Photon from Sun and travels with a velocity $c$. Now think we are that photon. For us, it looks like Sun is moving away from us with a velocity $c$. So, why don't we get attracted back ...
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1answer
118 views
Lepton masses in the Standard Model
Some simple questions regarding leptonic masses in the Standard Model (SM):
Why there is not an explicit mass term in addition to the effective mass term that arises from the Yukawa terms after ...
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1answer
217 views
The Strength Of A Black Hole
Does the gravitational strength of a black hole at its singularity change the more it pulls things into it?
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1answer
110 views
How to explain relativistic mass with 2 moving systems, but not 3?
All the visual explanations I know work in some kind of "If you are moving relative to something A, while inside A something is moving, the stuff in A has to move slower due time dilation and ...
