# Search results

1. ### Ultra high energy cosmic particles?

Cosmic Rays in general are believed to be created from supernova explosions in our galaxy and possibly from other galaxies. Protons are ejected from the explosion at extremely high velocities, although this doesnt completely explain where the extremely high energy comsmic rays (10^20 eV) come...
2. ### Energy conversion

ummm, a steam engine?
3. ### Need help in derivation

start off with the definition of acceleration... a = \frac{v_f-v_0}{t} v_f = v_0 + at Definition of average velocity... v_{ave} = d/t d = \frac{v_f + v_0}{2}t substitute... d = \frac{(v_0+at) + v_0}{2}t d = \frac{2v_0 + at}{2}t d = v_0t + \frac{1}{2}at^2 For the second...
4. ### Possbility of Time travel?

Ohhhhh...LOL, wow i was being dumb, i get what he meant now.
5. ### Possbility of Time travel?

??????????????????
6. ### Possbility of Time travel?

By saying "fast enough" im guessing you mean faster than the speed of light, which we all know is impossible. So from your example it would be impossible to time travel into the past, but it would be possible to time travel into the future because of time dilation. As for time travel to the...
7. ### Calculating The Event Horizon of a Supermassive Black Hole

I dont know much about black holes, but that equation you gave can be determined by knowing the mass of the black hole, since G and c are both constants. That bothers me a little, that you can calculate length from mass.
8. ### Light speeds

Is it true that light travels slower though a medium because the photons are absorbed and emited?
9. ### Light speeds

I dont think we will ever know why the constants of our universe are what they are, not only the speed of light, but also, planks constant, the gravitational constant, ect.
10. ### Altering the speed of light

Since everyday speeds are nothing compared to the speed of light, the length contraction/time dilation/mass increase are neglected. When moving at relativistic speeds (close to the speed of light) these effects are very noticable. For example, mass is a little more than 2 times greater at .9c...
11. ### Does maximum temperature exist?

Temperature is the measure of the kinetic energy of the particles, and relativistic KE is... KE = m_0c^2(\frac{1}{\sqrt{1-\frac{v^2}{c^2}}}-1) as v -> c, KE -> infinity
12. ### Temp. and air pressure

Actually, the exact opposite is true about what you said. First of all, pressure increases with temperature, and increasing pressure or temperature causes density to go down. Hence why hotter air rises and cooler air sinks. In fact a "high pressure system" that they refer to in forcasts always...
13. ### Mass of light

Interesting, I think i'll measure the weight of a lightbulb and then measure it again a few years later. That should be enough time for a significant change. So then what mass-energy conversion is going on when an electron and positron annihilate to create two gamma rays, if both the pair...
14. ### Static Charge

But water vapor in the atmosphere isnt "impure" like liquid water is from the ions disolved in it. The water vapor is pure water since you cant evaporate ions that were once in the liquid water. So, if what I say is true, then the reason why static charge builds up better in dry air is because...
15. ### Antimatter - could it ever be utilized as poss. energy source?

You did, the speed of light will never be reached or surpassed, even relative to another velovity. But people will eventually be able to have "warp drive". It sounds like something from Star Trek, lol and it is, but science fiction always has a potential of becoming science fact. Although it...
16. ### Visible spectrum

Yea, the visible part of the spectrum has the least range out of all of them.
17. ### Mass of light

Yes, that is exactly how I define as relativistic mass. The relationship come from Lorentz transformation. I dont know how that equation is derived, but do know how a similar one is, the equation for relativistic time. I love derivations so i'll make sure to find one online and take a look...
18. ### Why is the momentum of light equal to E/c?

I think you can derive it by simply using newtonian physics, but im not sure... F = \frac{p}{t} E = Fd = \frac{pd}{t} = \frac{mvd}{t} m = \frac{Et}{vd} p = mv p = (\frac{Et}{vd})v p = \frac{Et}{d} = \frac{E}{d/t} p = \frac{E}{v} Since light travels at c... p =...
19. ### Visible spectrum

Brown is a mix of color.
20. ### Why is the momentum of light equal to E/c?

I'll show how the equation Gonzolo showed tell you that p=E/c. E^2 = m_0^2c^4 + p^2v^2 <---Total energy of particle with rest mass, m_0, going at velocity v. Since light has zero rest mass and travels at velocity c... E^2 = p^2c^2 E = pc p = E/c
21. ### Lasing over the EM spectrum

I dont understand what lase means, and cant find a definition on google, please clarify.
22. ### Archimedes Principle proofs

The weight of the cube is not involved in the boyant force, it is only involved in whether the cube sinks or floats. The boyant force is due to the pressure variations at different depths in the water. Since the water pressure at depth h is \rho g h, where h is the depth from the surface and g...
23. ### Mass of light

Agreed Agreed, 0/0=undefined. I forgot that SR equations cant be used to tell what happens AT c. Thats strange because I though the word "relativistic" in general has to do with something close to the speed of light. For example "relativistic speeds" would be speeds close to c, and...
24. ### Mass of light

This is false, if something has zero rest mass then it must have zero relativistic mass because of SR equations. m=\frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}} If rest mass is zero, then relativistic mass must be zero as well because zero divided by anything is zero. Relativistic mass isnt...
25. ### What is Black matter ?

I've never heard of "black" matter, perhaps you mean dark matter. Dark matter is a kind of matter theorized to make up over 90% of the mass in the universe. It was theorized for different reasons, for example...stars in our galaxy were noticed to revolve around the center faster than they should...
26. ### Mass, volume, density

Are you allowed to use a sensitive balance to weigh the 3 objects?
27. ### Antimatter - could it ever be utilized as poss. energy source?

Thats why everything that happens must obey the conservation laws :smile:. If they disapeared without geting converted into anything, that would violate the conservation of mass and energy, E=mc^2. Momentum must be conserved as well, which is why then regular and anti particles annihilate to...
28. ### Does the light transform a matter?

No, that would give you the maximum mass into which that photon of light can be transformed into.
29. ### Altering the speed of light

Actually light cant have relativistic mass because of SP equations... m = \frac{m_0}{\sqrt{1-\frac{v^2}{c^2}}} As you can see, if something has a rest mass(m_0) of zero, then the relativistic mass is zero as well because zero divided by anything is zero. Lightspeed is a constant finite...
30. ### Antimatter - could it ever be utilized as poss. energy source?

Im not sure what you mean by "react negatively" but matter and antimatter annihilate each other when they touch, in other words they get converted completely into energy. So, we WANT them to "react" with each other, because the energy relased from it is a very good prepelant for spaceships if we...