Relativity & Mass Increase: Is it Just a Momentary Expansion?

In summary, the conversation discusses the concept of relativity and how as velocity approaches the speed of light, mass increases. One individual questions if this would cause the object to slow down, and another explains that the increase in mass is in the form of photons and does not affect the object's speed. The conversation also delves into the concept of mass and energy being equivalent, with a brief explanation of how matter can be converted to energy through chemical reactions.
  • #1
sudar_dhoni
90
0
relativity states that as v approaces c mass increases
but my question is that if we are going fast and suddenly mass increases then simultaineously we must slow down and thus we will be back to original state
by this hypothesis i believe that mass expansion is only for minute seconds
AM i right ?
 
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  • #2
sudar_dhoni said:
relativity states that as v approaces c mass increases
but my question is that if we are going fast and suddenly mass increases then simultaineously we must slow down and thus we will be back to original state
by this hypothesis i believe that mass expansion is only for minute seconds
AM i right ?

Increasing mass of a body would not slow it down. The mass increase as one approaches the speed of light is in the form of photons. The energy that is applied to accelerate a body as it approaches the speed of light turns into photons rather than pushing the body faster.


Frank
 
  • #3
frankinstein said:
Increasing mass of a body would not slow it down. The mass increase as one approaches the speed of light is in the form of photons. The energy that is applied to accelerate a body as it approaches the speed of light turns into photons rather than pushing the body faster.


Frank

cant understand could u PLZ explain in detail
and also
if possible can u explain how mass is converted to energy and energy is converted to mass
i can't understand how this happens. I want the physical meaning behind this
i console myself by thinking of this example: the food we eat is mass . It is getting digested to give energy so mass is converted to energy. But i am sure that this is wrong
 
  • #4
sudar_dhoni said:
cant understand could u PLZ explain in detail
and also
if possible can u explain how mass is converted to energy and energy is converted to mass
i can't understand how this happens. I want the physical meaning behind this
i console myself by thinking of this example: the food we eat is mass . It is getting digested to give energy so mass is converted to energy. But i am sure that this is wrong

Mass and energy are equivalent by E = mc[tex]^{2}[/tex]. So a body's mass can be increased by adding energy in the form of photons. The conversion of mass to energy and vicesa versa just happens. Its a process of matter that is simply accepted.
 
  • #5
frankinstein said:
Mass and energy are equivalent by E = mc[tex]^{2}[/tex]. So a body's mass can be increased by adding energy in the form of photons. The conversion of mass to energy and vicesa versa just happens. Its a process of matter that is simply accepted.

but photon has zero mass how can addition of photon increase mass also what is the source of photons
 
  • #6
sudar_dhoni said:
my question is that if we are going fast and suddenly mass increases then simultaineously we must slow down and thus we will be back to original state

You can increase the speed of an object only by pushing on it with something. The object that is doing the pushing does work on the pushed object, which increases the pushed object's kinetic energy according to the work-energy theorem:

[itex]K_{final} = K_{intitial} + W[/itex]

This in turn increases the pushed object's total energy

[itex]E = m_0 c^2 + K[/itex]

where [itex]m_0[/itex] is the pushed object's "rest mass," and the "relativistic mass" increases along with the energy according to [itex]E = mc^2[/itex].

Both the total energy and momentum of the object vary with speed differently in relativistic mechanics than in classical mechamics:

[tex]E = \frac {m_0 c^2} {\sqrt {1 - v^2 / c^2}}[/tex]

[tex]p = \frac {m_0 v} {\sqrt {1 - v^2 / c^2}}[/tex]

instead of

[tex]E = \frac{1}{2}m_0 v^2[/tex]

[tex]p = m_0 v[/tex]

frankinstein said:
The mass increase as one approaches the speed of light is in the form of photons. The energy that is applied to accelerate a body as it approaches the speed of light turns into photons rather than pushing the body faster.

No. Photons are not involved in this, unless of course you are accelerating the object by using photons, as in a solar sail. But here the photons are what is doing the "pushing," and they either disappear or are reflected backwards, depending on whether the sail absorbs or reflects light.
 
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  • #7
i can't understand einsteins mass energy equivalence that how mass can be converted to energy also the concept of rest mass and rest energy
what i thought about mass converted to energy is that

the food we eat is mass . It is getting digested to give energy so mass is converted to energy. But i am sure that this is wrong.
if possible can u also derieve E=mc2
 
  • #8
sudar_dhoni said:
the food we eat is mass . It is getting digested to give energy so mass is converted to energy.

Digestion is a series of chemical reactions. In any spontaneous chemical reaction, the sum of the masses of the reactants is greater than the sum of the masses of the products. The difference in mass (which is very tiny) corresponds to the energy released in the reaction.

But i am sure that this is wrong.

Why? (It's dangerous to be sure something is wrong before you fully understand it. :wink:)
 
  • #9
jtbell said:
You can increase the speed of an object only by pushing on it with something. The object that is doing the pushing does work on the pushed object, which increases the pushed object's kinetic energy according to the work-energy theorem:

[itex]K_{final} = K_{intitial} + W[/itex]

This in turn increases the pushed object's total energy

[itex]E = m_0 c^2 + K[/itex]

where [itex]m_0[/itex] is the pushed object's "rest mass," and the "relativistic mass" increases along with the energy according to [itex]E = mc^2[/itex].

Both the total energy and momentum of the object vary with speed differently in relativistic mechanics than in classical mechamics:

[tex]E = \frac {m_0 c^2} {\sqrt {1 - v^2 / c^2}}[/tex]

[tex]p = \frac {m_0 v} {\sqrt {1 - v^2 / c^2}}[/tex]

instead of

[tex]E = \frac{1}{2}m_0 v^2[/tex]

[tex]p = m_0 v[/tex]



No. Photons are not involved in this, unless of course you are accelerating the object by using photons, as in a solar sail. But here the photons are what is doing the "pushing," and they either disappear or are reflected backwards, depending on whether the sail absorbs or reflects light.

You're right it means that kinetic energy is not realize as linear higher velocity as the object is pushed towards the speed of light.
 
  • #10
sudar_dhoni said:
i can't understand einsteins mass energy equivalence that how mass can be converted to energy also the concept of rest mass and rest energy
what i thought about mass converted to energy is that the food we eat is mass . It is getting digested to give energy so mass is converted to energy. But i am sure that this is wrong.
if possible can u also derieve E=mc2
Most of our food energy comes from the oxidation of carbohydrates, such as the monosaccharide C6H12O6 (dextrose). The available energy is about 29 eV per molecule. The gram molecular weight is about 180 grams, so very roughly Mc2 is 180 AMU or 931 MeV x 180 = 167,000 MeV. So the available chemical energy is about 0.2 parts per billion.
Bob S
 
  • #11
You are probably thinking that momentum conservation implies if the mass is higher the velocity must be slower. But remember, to increase the velocity in the first place you are adding momentum to the system. So the velocity and mass can both increase simultaneously. Some of the momentum goes to increasing the velocity, and some to increase the mass. The amount of this which is divided between the two depends on the object's speed. If v is close to c, the object will hardly accelerate, but gain a significant amount of mass. If v is near zero, the additional mass will be tiny.
 
  • #12
MikeyW said:
You are probably thinking that momentum conservation implies if the mass is higher the velocity must be slower. But remember, to increase the velocity in the first place you are adding momentum to the system. So the velocity and mass can both increase simultaneously. Some of the momentum goes to increasing the velocity, and some to increase the mass. The amount of this which is divided between the two depends on the object's speed. If v is close to c, the object will hardly accelerate, but gain a significant amount of mass. If v is near zero, the additional mass will be tiny.

ok done but what is the source of that momentum which increases both mass and velocity
 
  • #13
sudar_dhoni said:
ok done but what is the source of that momentum which increases both mass and velocity
Fermilab routinely puts about 1012 protons, and 1012 anti-protons (in opposite directions) in the Tevatron (a 6280-m circumference synchroton), accelerates them to over 980 GeV total energy using RF cavities, where they can coast all day (synchroton radiation is not a significant problem). The RF cavities are the source of the added momentum. The mass is not increased, but the total energy is.
Bob S
 
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1. What is the theory of relativity?

The theory of relativity, proposed by Albert Einstein, is a theory in physics that explains the relationship between space and time. It states that the laws of physics are the same for all observers in uniform motion and that the speed of light is constant in all inertial frames of reference.

2. How does relativity affect mass and energy?

According to Einstein's famous equation, E=mc^2, mass and energy are interchangeable and can be converted from one form to another. This means that as an object's energy increases, its mass also increases. This is known as mass-energy equivalence and is a fundamental principle of the theory of relativity.

3. What is meant by "momentary expansion" in the context of relativity and mass increase?

In the theory of relativity, the concept of "momentary expansion" refers to the temporary increase in an object's mass as it approaches the speed of light. This is due to the object's energy increasing, and thus its mass increasing as well. However, this increase in mass is only momentary and does not affect the object's overall mass or size.

4. How does relativity explain the observed increase in mass of particles at high speeds?

In relativity, mass is not a constant value but rather a variable that depends on an object's velocity. As an object's speed approaches the speed of light, its mass also increases. This is because the object's energy increases, causing an increase in its mass, as explained by the mass-energy equivalence principle.

5. Is the increase in mass due to relativity a real physical phenomenon?

Yes, the increase in mass of an object at high speeds is a real physical phenomenon that has been observed and measured in experiments. It is a consequence of the mass-energy equivalence principle in the theory of relativity and has been confirmed by numerous experiments and observations.

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