|
physics anyone? (pg. 5)
|
View this Thread in Original format
| NeoPhono |
| quote: | Originally posted by hiram
bringing this back from the dead.. but i was wondering if all color light travels at the same speed or does their speed vary? every color light has a diffrent wavelength so im guessing their speed varys not by much. also, when the speed of light is mentioned.. is that white light? |
Through a vacuum same speed, through a medium different speeds (think prism). Speed of light is through a vacuum...doesn't matter what "color." |
|
|
| Sunflower |
| quote: | Originally posted by NeoPhono
Through a vacuum same speed, through a medium different speeds (think prism). Speed of light is through a vacuum...doesn't matter what "color." |
does that also apply to other things like radio waves |
|
|
| hiram |
bringing this one backkk...
refresh my memory.. how does the theory go saying once you approach the speed of light any given object tends to expand therefore never fully reaching the speed of light?? this being the reason why particle accelerators can never reach the speed of light. |
|
|
| deejaymara |
| quote: | Originally posted by hiram
bringing this one backkk...
refresh my memory.. how does the theory go saying once you approach the speed of light any given object tends to expand therefore never fully reaching the speed of light?? this being the reason why particle accelerators can never reach the speed of light. |
well, im not quite there yet (lord knows ill see plenty of it though)... but this reminds me of math where a function can get so extremely close to its asymptote at zero for example, but nevar actually touches it... 1/10, 1/100, 1/1000,... 1/1,000,000,000,000 etc.
yes i know, this doesnt quite answer ur question but i felt like saying it to make myself feel just a LITTLE bit smarter. :p |
|
|
| NeoPhono |
| quote: | Originally posted by hiram
bringing this one backkk...
refresh my memory.. how does the theory go saying once you approach the speed of light any given object tends to expand therefore never fully reaching the speed of light?? this being the reason why particle accelerators can never reach the speed of light. |
I've think you might be throwing a little bit of black hole physics in there (or at least a reference frame "paradox"). To your question; as a non-zero mass object approaches the speed of light, both its mass and energy required to reach the speed of light become infinite. The closer you get to the speed of light, the more massive the object becomes and the more energy you need to go faster. Eventually you reach the point where the object is too massive and the energy required too extreme to accelerate the object any faster.
So even the particles in particle accelerators (which have mass) eventually require too much energy to be accelerated any faster.
...and no, E=mc^2 doesn't tell you how much energy would be needed to accelerate an object of mass "m" to the speed of light, but how much energy a mass "m" is equivalent to. (Not that you said that, but I've heard people try to say that before.)
Anyone on here to back me up? |
|
|
| Lebezniatnikov |
That was a good response. A much simpler explanation than my AP Physics teacher was able to give back in the day.
:) |
|
|
| Omega_M |
| quote: | Originally posted by NeoPhono
I've think you might be throwing a little bit of black hole physics in there (or at least a reference frame "paradox"). To your question; as a non-zero mass object approaches the speed of light, both its mass and energy required to reach the speed of light become infinite. The closer you get to the speed of light, the more massive the object becomes and the more energy you need to go faster. Eventually you reach the point where the object is too massive and the energy required too extreme to accelerate the object any faster.
So even the particles in particle accelerators (which have mass) eventually require too much energy to be accelerated any faster.
...and no, E=mc^2 doesn't tell you how much energy would be needed to accelerate an object of mass "m" to the speed of light, but how much energy a mass "m" is equivalent to. (Not that you said that, but I've heard people try to say that before.)
Anyone on here to back me up? |
That's pretty much it I guess.
As a particle accelerates, its kinetic energy increases and because of the energy mass equivalence through E=mc^2, increase in energy => increase in mass and thus the particle becomes heavier. A heavier particle requires more external energy to accelerate it further which in turn adds more mass. This process if taken to its logical conclusion implies that a particle of infinite mass will need infinite energy to accelerate it to the speed of light, which is impossible. Hence particles with non-zero mass can never reach the speed of light. |
|
|
| Capitalizt |
I still don't understand how the energy used to push something actually ADDS to the weight of that 'thing'...
How does kinetic energy = mass? When I expend energy in throwing a a baseball, does it gain weight as it flies through the air? Then lose weight when it hits the ground?
I also don't get the whole "expanding" idea as objects are accelerated towards light speed.. Does the length of the baseball also expand when thrown? |
|
|
| NeoPhono |
| quote: | Originally posted by Capitalizt
I still don't understand how the energy used to push something actually ADDS to the weight of that 'thing'...
How does kinetic energy = mass? When I expend energy in throwing a a baseball, does it gain weight as it flies through the air? Then lose weight when it hits the ground?
I also don't get the whole "expanding" idea as objects are accelerated towards light speed.. Does the length of the baseball also expand when thrown? |
Gotta run unfortunately (cause I love this stuff), but about your first part...
m = m0 /sqrt(1 - v2/c2)
m = mass, m0 = initial mass
So as velocity (v) approaches the speed of light (c), the denominator approaches zero and m approaches infinity.
Probably not very satisfactory as to the "why" but maybe a little math behind it will muddy it up a little more. :) |
|
|
| Shakka |
| quote: | Originally posted by Capitalizt
I still don't understand how the energy used to push something actually ADDS to the weight of that 'thing'...
How does kinetic energy = mass? When I expend energy in throwing a a baseball, does it gain weight as it flies through the air? Then lose weight when it hits the ground?
I also don't get the whole "expanding" idea as objects are accelerated towards light speed.. Does the length of the baseball also expand when thrown? |
I'm not deeply involved in this thread but I think you may be confusing "adding weight" with momentum and the associated force. F=MV^2
Otherwise I think the question starts to delve into relativity but I don't think relativity is relevant when talking about baseballs and speeds that are minuscule relative to the speed of light. |
|
|
| Krypton |
| Mass and energy are the same thing? WHAT?! I wonder if I can be converted to energy right now? A human atomic bomb!! |
|
|
| DJ Shibby |
| quote: | Originally posted by Krypton
Mass and energy are the same thing? WHAT?! I wonder if I can be converted to energy right now? A human atomic bomb!! |
A ha! You're on to something. |
|
|
|
|
