# 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. ### Light, Mass, and Black hole question

for particles with a non-zero rest mass... m = \frac{m_0}{\sqrt{1 - \frac{v^2/c^2}}} This equation gives you the mass of a particle relative to you, going at velocity v. particles with a zero rest mass, for example, photons, naturaly travel at the speed of light, they cannot travel slower...
4. ### 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...
5. ### Possbility of Time travel?

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

??????????????????
7. ### 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...
8. ### An incline problem

I think the acceleration would be -g*cos(35), from that use constant acceleration equations to solve the problem.
9. ### Average Speed?

This problem in general is very dumb because it implies an instantaneous change in speed from 55km/h to 90km/h.
10. ### Average Speed?

The solution offered in the very biginning, \overline {v} = {v_0 + v_f \over 2} only works if assuming constant acceleration.
11. ### Proton and neutron

This is impossible, the mass of the proton is 1.67262158 × 10-27 kilograms, while the mass of the electron is 9.10938188 × 10-31 kilograms. This means that the proton has a mass more than 10^4 times that of the electron.
12. ### Heat at work

1) The direction of the atoms are completely random according to the Kinetic Molecular Theory. 2) Only the atoms move, the protons and neutrons are fixed in the atom as being the nucleus with electrons "rotating" around the nucleus. If the atoms move fast enough, some atoms will get ionized...
13. ### Neurinos are massless paricles

Neutrinos are definitly not massless, they have a rest mass. Particles with no rest mass, for example photons, DO have energy, which can be calculated by using the equation... E = h \nu Where E is the energy, h is plank's canstant and \nu is frequency of the light.
14. ### 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.
15. ### How cavendish determined the value of G

So, what did he use to bounce off the mirror?
16. ### How cavendish determined the value of G

Cadendish used a laser to bounce off a mirror on the balls and see the angle that the light beam creates after the balls attract each other. I dont know how he exactly used this to calculate it, I've heard that Cavendish calculated G by accident, that he was origionally trying to calculate the...
17. ### Pressue due to Ideal Gas

This is a well known and often used equation, if u want to see derivations just google it. I found some by googling "derivation root mean square velocity". http://itl.chem.ufl.edu/2041_f97/kin_thr/kin_thr.html [Broken] http://pitons.uwaterloo.ca/chem350/Resources/pressurederiv.pdf [Broken]
18. ### Light speeds

Is it true that light travels slower though a medium because the photons are absorbed and emited?
19. ### 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.
20. ### Pressue due to Ideal Gas

Its actually a manipulation of the ideal gas law combined with the equation for the rms of a molecule. PV = nRT PV = \frac{mRT}{M} where m = mass of molecule and M = moler mass. P = \frac{(m/V)RT}{M} = \frac{\rho RT}{M} c_r_m_s = \sqrt{\frac{3RT}{M}} c_r_m_s^2 =...
21. ### Electric fields and electrostatic forces

Electric field, E = \frac{kq}{r^2} Since you have two particles with charges, lets call the unknown charge q1, and the known charge q2, where Since E = 0, \frac{kq_1}{r^2} + \frac{kq_2}{r^2} = 0, where r is the distance from the charge to the point of zero electric field. Therefore... For...
22. ### 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...
23. ### 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
24. ### 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...
25. ### 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...
26. ### 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...
27. ### 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...
28. ### Visible spectrum

Yea, the visible part of the spectrum has the least range out of all of them.
29. ### 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...
30. ### 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 =...