# Search results

1. ### How cavendish determined the value of G

So, what did he use to bounce off the mirror?
2. ### 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...
3. ### 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]
4. ### 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 =...
5. ### Gravity and angular momentum

You are right, centrifugal force doesnt actually exist, its only an effect that gives a force outward. Since all objects in motion want to stay in motion in a straight line...the constant spinning and changing in direction causes an outward "force". Angular momentum is what is actually present...
6. ### Back in time by going faster than light?

I've heard that many times too, but never understud why either. I think its a bunch of crap when they say that. I think the only reason they say you will "go back in time" is because the the maximum speed at which information can be transfered is the speed of light. Going faster would mean you...
7. ### Generators: Water instead of a coil?

Yes, and with water you have many problems because theres only so much you can disolve in it in order for it to have ions. While with metals, you dont have the problem since its already conductive and plus is can be made superconductive if cooled.
8. ### Does Temperature affect the coeffecient of friction?

There are a lot of factors involved. For example, at 40 degrees the water vapor in the atmosphere would condense slightly on the pavement, making the road much more slippery and low in friction. Depending on the day, the water might mix with settled dust on the road, making a small layer of...
9. ### Does Temperature affect the coeffecient of friction?

That makes sense, but I thought that hot brake pads have less friction because they are expanded from normal.
10. ### Generators: Water instead of a coil?

That makes sense because liquid hydrogen is at almost obsolute zero, which means any current that goes through it will have very very little resistance, making it very conductive. Now that i think about it, it would be awsome to have a coil of wire in a generator which would be surrounded by a...
11. ### Generators: Water instead of a coil?

Using water in place of a coil is a terrible idea. Generators work by spinning a roter in the magnetic field of permanent magnets. The rotor has a coil of conductive wire, and as a conductor is moved through the magnetic field by spinning, it causes the flow of electrons in the conductor, which...
12. ### Generators: Water instead of a coil?

I not sure I understand...are you saying we should use water with electrolytes instead of a coil of wire in the generators? How do you expect the water to help produce greater electricity if you cant even coil it. Having the coil move through the magnetic field can generate a lot more power than...
13. ### Where does 1/2 come from in 1/2kx^2?

Thanks for the tip. :smile: Yes, I already know that...
14. ### Where does 1/2 come from in 1/2kx^2?

Oh wow, that makes sense, at least the explanations without the use of "intergration" or "derivative" and that calculus stuff. I have no idea what those words mean, although ive heard them many times. I'm going to take BC calc when school starts. Anyways, thanks a lot for the responses. :)
15. ### Where does 1/2 come from in 1/2kx^2?

errr....I havnt taken calculas yet, so i have no idea what that means, lol.
16. ### Where does 1/2 come from in 1/2kx^2?

Where does 1/2 come from in 1/2kx^2?? Sorry is this sounds like a silly question, but i was just wondering where the 1/2 in PE = 1/2kx^2 comes from. If F=kx, then wouldnt it be kx*x = kx^2 ?
17. ### Air in Tire Question

JohnDubYa, did u even read everything in the post i had? In that post i was using the tire on a moving car.
18. ### Air in Tire Question

There are several factors involved in this situation...so its hard to tell now. You have bernouli affects, centripital acceleration, friction against the ground. Lets think about this, the car is moving, since air has very little friction, it takes a long time for it to start circulating. When...
19. ### Would a Hot star have more mass than a cooler one?

The whole point i was making wasnt star evolution, but the fact that if one star has a greater temperature than the other then that would mean that the atoms that the star is made up of have a higher kinetic energy and therefore a higher speed. Mass is relative to speed, so if the atoms of one...
20. ### Air in Tire Question

Why would the air be circulating in the first place? But if it were, and it slowed down...then the pressure would increase. This is because traveling air has lower pressure, which is called the venturi effect (sp?).
21. ### Would a Hot star have more mass than a cooler one?

Hey all, sorry about the confusion. By saying identical stars, i meant that the stars (if would be the same temperature) would have the same mass, and i guess the same concentration of H and He atoms, although i dont think thats neccasary to say in this case. Lets just say you first have 2...
22. ### Would a Hot star have more mass than a cooler one?

If you had 2 identical stars, one was a very hot star, but the other was cooler. Since mass is relative to velocity, shouldnt the hotter star be more massive than the cooler one since the atoms in the hotter star would have more kinetic energy and therefore a higher speed?

24. ### How is this equation derived?

its good, but i like gerben's better
25. ### Electric field of two polar molecules

I'm lost overall about what the discussion is about, are u talking about the polarity of molecules?
26. ### How does it work?

Yea, he's right about everything. Besides, we're just not going to anytime soon have engines powerful enough to go anywhere close to the speed of light, not even a quarter. Nuclear fusion engines are being worked on right now i believe, but that wont be enough to make space travel that short...
27. ### How does it work?

Alrite, I think i know enough about antimatter to answer your question. First of all, antimatter is actually very much like matter, but it has a different charge. What i mean by that is...antiprotons have a negavity charge, positrons(antielectrons) have a positive charge, antineutrons are still...