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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2answers
43 views

Why the mobilities of holes and electrons are not identical in an intrinsic material?

In an intrinsic material, the lifetime $\tau$ of electrons and holes is the same, so in the equation for mobility, $$\mu = \frac{e\tau}{m^*}$$ the only difference between mobility of electrons an ...
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1answer
122 views

How to measure the mass of the lower part of a human body?

An Olympic weightlifter asked me this question and it has been bugging me for a couple of days now. Suppose "lower part" is defined as anything below and including the hip. This means that the ...
3
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1answer
117 views

Is it experimentally proven that photons travel at speed $c$ in vacuum?

Are there experiments which show that single photons (not classical em waves) travel exactly at $c$ in vacuum? What is the error bar in that case? The question is posed due to the fact that loop ...
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4answers
9k views

If you double the mass of a moving object - is its kinetic energy quadrupled?

My colleagues and I were having a layman conversation about fuel consumption of boats vs planes etc. I was pointing out that according to the formula $$ E_k = \frac{1}{2}mv^2 $$ if you double the ...
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2answers
189 views

At What Point Does Mass Cease to Matter?

I know very little about physics so I naturally have a lot of simple minded questions. Assuming I am piloting a rocket and want to obtain the fastest speed possible. At what point does mass more ...
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2answers
468 views

For a particle to have physical mass, is it always necessary to have a mass term in the lagrangian?

Since the self-energy adds to the bare mass defined in the Lagrangian, is it possible to create a physical particle mass from the self-energy alone, with no mass terms occuring in the Lagrangian? On ...
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1answer
642 views

How is the fall time for a parachute affected by the mass of the load?

Why do parachutes with a heavier load fall faster than a parachute with a lighter load?
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3answers
71 views

Are all conserved scalars proportional to relativistic mass? [closed]

I have read in Rindler's relativity book that all scalars depend only on the magnitude of velocity of a particle and that are conserved are proportional to relativistic mass. ...
1
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0answers
26 views

Simulating Debris Burn Up Upon Atmospheric Reentry

For work I need to model Debris (1 gram to no more than 1000 km) burn-up upon reentry. I can't seem to find much information regarding this. I feel like I am looking for the wrong terms or something. ...
4
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1answer
12k views

Terminal velocity of two equally shaped/sized objects with different masses?

I've tried doing research on this and there are some similar questions. However, they have slightly different scenarios and to make sure I understand things perfectly, I wanted to word it into my ...
9
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5answers
9k 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" ...
3
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1answer
1k views

What bends fabric of space-time?

I know that mass can bend fabric of space-time, which causes gravity by making an object curve around a planet or star but is there anything else that can bend it? Other energy sources, forces ...
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1answer
45 views

What is the property which flows as described by the stress energy tensor in GR?

I found the following definitions: The stress–energy tensor (sometimes stress–energy–momentum tensor or energy–momentum tensor) is a tensor quantity in physics that describes the density and flux of ...
3
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0answers
50 views

What is the inertial mass of a black hole?

Or the inertial mass of any spherically symmetric object, can I calculated by measuring very accurately the spacetime distortion this object produces in its surroundings? With 'inertial mass' I mean ...
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3answers
115 views

How does a mass create the gravitational field of GR? [closed]

As far as I understand, and please correct me if I am wrong, but the basic idea of general relativity is that spacetime is curved by matter. What we call gravity is then not a force as per Newton but ...
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2answers
131 views

At relativistic speeds, how is an object's increased mass created and distributed?

This question says that, at relativistic speeds, an object's increased mass will result in increased weight or gravitational force. But if we have increased mass and corresponding gravitational ...
1
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1answer
97 views

Reason for not using Higgs mechanism to solve mass gap problem

I am curious as to precisely why one can't introduce masses for gluons in Yang-Mills by a Higgs-type mechanism as in electroweak theory. Is it because then one would end up with an unwanted massless ...
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0answers
38 views

Calculating electricity used for weights on an elevator

Given an elevator with a motor driven by a power supply, torque ability and a pulley does it take more electricity to lift more people? I have some of the calculations but do elevators lift at a set ...
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1answer
141 views

Is it true that the standard model does not predict the mass of the electron?

I read that the standard model has parameters that have to be put in such as the mass of the electron, because nobody has been able to calculate the mass of the electron. Is this true?
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4answers
4k views

How is inertial mass different from gravitational mass? [duplicate]

I recently read that the mass we deal with in Equation $F=M_{i}a$ is called inertial mass and the mass we deal with in $F=M_{g}g$ is gravitational mass. Suppose I take a ball in a free fall and in ...
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0answers
17 views

if a meteorite is moving in space fast enough to generate a lot of mass shouldn't it generate gravity because its moving? [duplicate]

is it how planets form when is happens to have alot of mass to generate a little bit of gravity, oh and bullets for example they generate mass when moving and causes it generate mass?
2
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1answer
126 views

gravity cancelling dark energy

Say there were 2 objects with certain masses (e.g. $m_1$ and $m_2$). If they were close together gravity would attract the 2 objects. If they were a large distance apart the expansion of the universe ...
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2answers
97 views

Rest mass energy of electron

For electron's energy why we some time use the word "REST MASS ENERGY" why we use this word as electron is always spinning? ...
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3answers
404 views

Zero $g$ in a black hole?

At the very centre of the Earth, masses cancel each other out, creating an effective zero-$g$ environment. Would the same happen in a black hole?
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2answers
62 views

Period of mass in circular motion [closed]

I've been trying for 4 days now to solve my physics lab assignment but now I'm starting to think there must be a mistake in the question. You know those rotating mass experiments where you have a mass ...
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0answers
23 views

Is photon massless? [duplicate]

if photon is massless then in E2=m2c4+p2c2 is m=0 ? and p=mv1-mv2 shouldnt be zero too. if both the statements are true then does photon has no energy?
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1answer
55 views

3D donuts and the centre of a black hole [closed]

I have been trying to imagine ways to visualise the gravitational field of the earth... It's near zero at the outer edges of the atmosphere, strong at sea level, strongest at the quarter point, then ...
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2answers
68 views

Does it take a larger force to stop a faster object?

Does it take a larger force to stop a car that is moving at a velocity 2*v than if it is moving at a velocity v? I'm confused as the force required to decelerate a car depends on the mass and the ...
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1answer
60 views

Effective mass of two objects

I read that if we want to perform conservation of energy taking one object as frame of reference, we need to assume that the other object has the effective mass and velocity. And effective mass is ...
9
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3answers
1k views

How can neutrinos oscillate though the lepton flavors have differing masses?

Since the total mass-energy for the neutrino presumably does not change when a neutrino changes lepton flavor, though the mass is different, what compensates for the gain or loss of mass? Does the ...
2
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3answers
41 views

What is the gravitational pull if one has as much mass above them as below them? [duplicate]

I understand the previous responses to other answering if you were at the center of a planet, would you be weightless? Yes you would due to the forces of gravity pulling at you from all sides. ...
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0answers
35 views

What is $r$ in angular momentum quantization rule?

We know $$mvr= nh/2π $$ What is $r$ here if I consider positronium system. I suppose it should be the radius of the orbit in which both are moving. But when I take the above equation and electrostatic ...
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1answer
35 views

How to calculate relativistic mass versus time?

I know that relativistic mass is calculated as: But when mass m0 gets bigger, also mass of the accelerating body mass m gets bigger so m0 gets bigger and so on. So if body accelerates with ...
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2answers
57 views

Double the mass in the universe, double the inertia

If I double (halve) the mass in the visible universe, will my inertia double (halve)? I think it should, at least as soon ''I have received the news of this doubling''. But what does the General ...
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2answers
45 views

Remotely finding the mass of a satellite

I have a question similar to one I've asked earlier (Calculating mass of an orbiting body with force and acceleration), but without a specific formula... How can you find the mass of a satellite body ...
2
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1answer
87 views

Calculating mass of an orbiting body with force and acceleration

I'm new to physics, and it's a lot to take in- but there is a problem that I really can't seem to wrap my head around- finding the mass of an orbiting body, like an asteroid. I've looked around a lot ...
2
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3answers
420 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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6answers
4k views

If there is no gravity, does that mean there's no mass as well? [duplicate]

I have demonstrated that weight only is measured based on the gravitational pull of where you live. For example, the gravity on the surface of Mars is three times smaller than the gravity on the ...
3
votes
3answers
94 views

Why does a teeter-totter (see-saw) tend to incline towards the heavier end?

Why does a teeter-totter (see-saw) tend to incline towards the heavier end? Since objects of different mass tend to fall at the same speed (assuming a vacuum), why do then heavier objects push harder ...
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2answers
75 views

Negative Mass Square

I'm reading a book about neutrino physics (from 1997). In the chapter about neutrino mass they list results of certain experiments. All of them get a negative value for $m(\nu_e)^2$ but a positive one ...
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1answer
72 views

Constructing a Hamiltonian from a mass matrix?

I was solving some questions regarding the Hamiltonian, which required a lot of algebra, but as I finished and looked professor answer I saw that he constructed a matrix from the kinetic energy and ...
3
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3answers
2k views

Does a toy top weigh less when it is spinning?

I am under the understanding that a toy top will weigh less when it is spinning. The Russians made a spinning type transport back in the 70s to lessen its payload over the tundra. Is this an effective ...
5
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3answers
2k views

What is the mass of a wave?

The slide called "QUANTA" here says that "One Quantum has a definite mass" and the picture shows a wave. So, What is meant by the mass of a wave?
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4answers
86 views

Proving that the Center of Mass of a solid sphere is at the origin [closed]

For my own knowledge and to understand why. I am trying to convince myself that the center of mass for a rigid solid sphere is at the origin (0,0,0). I begin with the basic definition of CM ...
8
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3answers
2k views

What defines the mass of elementary particle?

The electron is particle. The mass of electron is $9.10938215(45)\times 10^{−31}\, {\rm kg}$. But why is the mass exactly what it is? What in physics defines the mass of elementary particle?
2
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1answer
70 views

Mass - Unification of kinetic and gravitational mass definitions

As a kinetic definition, mass of a body is a measure of the translational inertia of the body. There is also the gravitational definition of mass. Can these definitions (kinetic and gravitational) be ...
0
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1answer
44 views

How to derive an equation for the mass of a pendulum bob?

How to derive an equation for the mass of a pendulum bob? If anyone knows of a resource that shows this (I've looked) or could explain how to derive an equation for the mass of a pendulum would be ...
5
votes
2answers
1k views

If quarks didn't have mass, could protons (and neutrons) exist?

I read here (mass of a proton) that the mass of a proton is mostly (99%) due to the energy of the strong nuclear force which binds the quarks together, and not the actual mass of the quarks. My ...
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0answers
42 views

Point of zero gravity for fixed masses?

Given a number of fixed point masses in 3D space, is there necessarily one or more points where there is zero gravity (ie, the combined gravity of the masses cancels out), and, if so, how do I find ...
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0answers
34 views

Charged Universe and charge-dependent inertia/anti-inertia

I posted this same question as a follow up for the main question here. I expected to get a quick answer but since none have come up I raise it as a topic in its own right. So the question is: Suppose ...