All Questions
221
questions
-6
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0
answers
77
views
Was relativistic mass necessary? [closed]
according to newton if velocity is constant then momentum will stay fix as mass would not change according to conservation of mass and if mass changer the newton will be wrong and if it does not then ...
- 1
0
votes
0
answers
26
views
Can two objects of different mass experience the same air resistance? [duplicate]
This question is assuming that the objects have the same shape and size, but different masses. I know that all objects have the same gravitational acceleration on earth, which is about 9.8 m/s^2. ...
- 539
1
vote
1
answer
89
views
How do objects with more mass accelerate when pushed downward?
This is kind of a simple question.
I was basing it off Newton's second law, $$F=ma$$
With the same applied force, an object with more mass will accelerate less.
However, what if two objects of unequal ...
- 539
0
votes
0
answers
19
views
How does mass-energy equivalence work with chemical bonds? [duplicate]
If you have, for instance, 2 oxygen atoms and do E=mc2 to get their equivalent energy, you get about 2.38nJ. However, if you have diatomic oxygen, there's also the energy of the bond; about 0.8aJ. ...
- 185
-1
votes
2
answers
78
views
Rest Mass Energy
What exactly is the Rest mass energy? I know the usual goes Like it is total energy stored in mass $m$ that is in Rest. so for someone moving relative to the frame that the mass $m$ is in (a rest ...
- 73
3
votes
2
answers
504
views
Is the mass of curved space, additional mass?
According to Einstein, mass, say in the form of matter, curves space. It is the curvature of space that gives rise to gravity. Now I have heard there is an energy associated with the curvature of ...
- 131
1
vote
4
answers
673
views
How does mass relate to kinetic energy?
I was working on homework and I had to list what kinetic energy depends on. Interestingly, it turns out it's also based on mass, not only speed. Does anyone have an explanation?
- 539
0
votes
3
answers
138
views
Why does an alpha particle traveling at the same speed as a beta particle have 'only' about twenty times the energy? Rather than over seven thousand? [closed]
An alpha particle travels at about half the speed as a beta particle, right? ~5% of light speed versus ~10%?
Therefore, if you doubled its velocity, its energy would roughly quadruple, correct? (Or ...
- 4,509
1
vote
2
answers
198
views
Equation for relative Kinetic energy
Relative Kinetic energy is given by
K.E = ($\gamma$-1)$m_0$c²; where $m_0$ is rest mass
but can it also be given by this
K.E= $\frac{1}{2}\gamma m_0v²$;
where v is velocity of particle
can it?
- 367
2
votes
8
answers
306
views
If matter is a form of energy, can it be converted into another form of energy?
I have been told that energy and mass are the same. What puzzles me is why don't we use the same units of measure for both if they are the same? The unit of mass is kg and the unit of energy is the ...
- 151
2
votes
3
answers
207
views
Energy and momentum & the relation between them
I am trying to wrap my head around energy, mass and momentum, especially in the more general scope of special relativity where massless objects moving at the speed of light also have momentum. So I am ...
- 219
0
votes
2
answers
71
views
Confusion in calculation of power [duplicate]
Question-
Sand is being dropped from a stationary dropper at a rate of 0.5 kg s$^{-1}$ on a conveyor belt moving with a velocity of 5 ms¹. The power needed to keep belt moving with the same velocity ...
- 252
0
votes
1
answer
30
views
Total energy "exertion" raising and lowering a weight
I'm thinking of the example of somebody raising and lowering some kind of weight, say a barbell and what effect the total time takes to perform the whole raising and lowering action would have on the ...
- 191
5
votes
3
answers
363
views
How is the energy content in 1 kg of water and petrol the same?
We know petrol is a fuel and water is not. But how come 1 kg of water and 1 kg of petrol have the same energy content? The total energy is given by $E=mc^2$, it says nothing about the chemical ...
- 179
0
votes
0
answers
36
views
Calculate Kinetic Energy of electron from effective mass?
The effective mass of an electron, due to special relativity, lower than the real mass. So I thought one can calculate from the mass ratio the velocity as it is dependent by a factor of $\sqrt{1-v^2/c^...
- 1
0
votes
1
answer
35
views
Massive equivalent of a photon and deduction of a photon's linear momentum
Since photons have an energy given by $E=h\nu$, we could define a particle whose rest mass is such that it has the same energy than the photon: $E=m_0c^2 \Longrightarrow m_0=\frac{h\nu}{c^2}$. We now ...
- 1,616
0
votes
3
answers
150
views
Can matter be mass and energy simultaneously? [closed]
I am well aware of the fact that this question is very elementary and I should not have posted it on StackExchange. I wouldn't have had, but most of the reddit forums where I ask questions have gone ...
- 95
5
votes
2
answers
850
views
Does kinetic energy rely on the observer mass too since velocity is relative?
There is no 'correct' inertial reference frame according to relativity. Objects are only 'in motion' relative to an arbitrary inertial reference frame. So let us take the following example. A person ...
- 1,009
-1
votes
1
answer
129
views
"Information Catastrophe" and measuring density of planets?
In the article https://arxiv.org/pdf/2009.01937.pdf the term "Information catastrophe" is explained. Suppose the later proposed experiment by this author https://aip.scitation.org/doi/10....
- 180
6
votes
3
answers
181
views
Why protons and neutrons don't have less mass than their constituents?
A system of gravitational attracted objects weight less than the sum of their individual masses because it needs energy to move them apart and overcome the gravitational attraction. Same is true for ...
- 793
1
vote
1
answer
277
views
Is effective mass used in calculating kinetic energy of electron in semiconductor?
Is effective mass used in calculating kinetic energy of electron in semiconductor? I recall it was just used to take into account the internal forces so that expression of force fits well. But why
$...
- 23
3
votes
2
answers
151
views
How does most energy get transfered to mass at high relavistic speeds, but mostly to movement at low speeds?
From what I understand about relativity, it is impossible to accelerate a massive object to the speed of light because it's mass would become infinite. Once an object is moving close to the speed of ...
- 79
0
votes
2
answers
408
views
Derivation of Energy-Mass Equivalence: Total energy = kinetic energy $+ mc^2$ [duplicate]
How do you derive the energy mass equivalence just from special relativity? To be exact, in this video, https://www.youtube.com/watch?v=KZ8G4VKoSpQ, at around 23 minutes in, he claims that the total ...
- 480
2
votes
1
answer
43
views
Change of velocity without doing work
Body of mass $1\rm\, kg$ is moving towards left side at velocity of $-2\rm\,m/s$ and is slowing down due to the constant external force until it stops. After that, it's speeding up towards the right ...
- 25
1
vote
3
answers
205
views
Considering $E=mc^2$, what really is a Joule?
A newton is defined as the force able to accelerate a mass of $1kg$ by $1m.s^{-2}$ : $1N=1kg.m.s^{-2}$.
Then, a joule is defined as the work done by a force of $1N$ moving an object by $1m$ : $1J = 1N....
- 193
1
vote
1
answer
85
views
Does the intrinsic energy of an object vary, if measured at different heights in a gravity field?
The gravitational redshift has different interpretations. Several quantities vary with height (or seem to), by the same equation - time, energy, mass. I wondered if measurements can shed some light on ...
- 85
0
votes
2
answers
80
views
Is there a proven causality that energy-matter causes curvature in spacetime?
I'm not very knowledgable in physics, sorry.
I've read and (somewhat) understood that energy-matter causes space-time to curve but I was wondering about the causality in the statement.
Is this ...
- 3
1
vote
3
answers
66
views
Besides traveling at the speed of light, how can we be sure that it is possible to have energy and momentum without mass?
How can we be sure that it is possible to have energy and momentum without mass? If something were to continually lose energy, would it not also lose a corresponding amount of mass? I understand that ...
0
votes
1
answer
34
views
Would it be possible to design a dart-like object such that it survives re-entry and impact at interplanetary / interstellar speeds?
I was wondering about spacecraft - specifically just getting from point A to B. If you were unconcerned about human survival and damage from g-forces, it would be much easier to deliver it without the ...
- 11
1
vote
2
answers
470
views
Nuclear fusion kinetic energy nucleons theory
Is this theory correct?
I got this theory from a nuclear fusion expert in stack exchange and he told me to confirm it here...
The theory:
When two nuclei come closer enough (due to external energy ...
