Classical Physics

What's the relation between the speed of a falling object and the air resistance? Why does the resistance increase with speed? Is that similar to liquid? When a heavy thing is thrown into water, it sinks with decreasing speed, right? But if an object falls down from a mountain, it falls with increasing velocity but decreasing acceleration. Why there is a difference between liquid and gases? Aren't both of them fluid? Could anyone help me?

Anyone got any good besides wikipedia ( good meaning simple to read for a simpleton like me, concise and to the point for a simpleton like me, and simple to read for someone with a short-term memory like me) sites regarding factors affecting the physics of falling dominoes? These factors may include but are not limited to: forces, vectors, gravitational potential energy, kinetic energy, momentum, energy conservation, or energy transfer. And, if you have any information pertaining to the physics of falling dominoes, whose surfaces are on parallel planes and are a constant distance away, could you post them here?

What exactly is variational mechanics and variational calculus ?

From what I know, speed of light is c in vacuum. However, it seems to slow down as it pass through transparent material like glass or water. I have learned that light has actually not slowed down as it pass through glass, it only appears to slow down. Actually, the speed of light is still c as it pass through glass, but the electronic polarization effects of the material causes EM energy to be absorbed through dielectric loss (due to the imaginary dielectric constant) and this in effect make light appear to us as having slowed down in the glass medium. Assuming magnetic effects of the EM radiation to be negligible in glass, we have the relationship refractive…

I'm doing this science experiment on the resistance of a wire. Factors that I have to examine are the length, thickness and the material that composed the wires. How should I set up my prac.? One of the requirements of my experiment is to include a lightglobe in my circuit. A diagram would be helpful. Thank you.

if there is an object with a mass of, say, 80 tons traveling at a rate of 236.9312m/s, hypothetically, and it hypothetically crashes into a wall, would you happen to know, offhand, the force of impact? or whatever it is that knocks the wall down.

I want to consult about the lightning. How the strongest of lightning being explained? The number of electrons? Would the lightning be invisible ?

Can anyone tell me the relationship (formulas?) between light intensity and current in a filament light bulb?

Imagine a projectile being launched up a frictionless plane inclined at 60 degrees to the horizontal.... with a velocity of 60 m/s. How can you use this two data given to determine the distance travelled by the particle up the plane and the time taken for it do that?? I was quite confused by this since i get differing answers to distance using different methods. If I find t by t=u*sin 60/g... and plug the t value in s=u*sin 60*t - 1/2*9.8*t^2.... I get the distance as 137m. But my teacher uses the equation v^2 = u^2 - 2*9.8*sin 60*s taking v=0 and gets the distance as 212m. So in a nutshell, I am stuck... I got my exams tomorrow... so if any1 could solve this out…

hey what up again. ummmm... a couple weeks ago, i had to do a project for science to make a machine give as much work output as work input(obviously impossible, but he wanted us to get as high as we could). well i got a 92 on the project,but i only got about 50% output i think. he didn't give us a way to gauge it. does anyone know if there is a perfect machine? and if there isn't, what do you think would mae one. i know if someone figured it out, a nobel prize would be hanging on there wall, i just want to hear some of your opinions.

Hi ya, I am given a force field F(x,y,z) and i want to find a potential V(x,y,z) such that grad(V)=-F. then I get three partial differential equations Vx=f(x,y,z) Vy=g(x,y,z) Vz=h(x,y,z) how do u find V from those three. cheers

Hello, I am posting this thread in hopes of finding a possible solution to my dilema for a science project. The objetive of the project is to be able to keep a raw Large egg protected after being dropped from 6 feet. Except...there is a catch..the only materials I am able to use are: 20 plastic straws, 10 rubber bands, and 1 meter of standard masking tape. If anyone has any ideas or suggestions, PLEASE comment! Thanks!

a capacitor basicly consists of 2 conductive plates seperated by a dielctric. the dielectric can be Air, or even a vacuum, as thermionic Valves have capacitance ratings between internal conductors. so could 2 metal plates in Space be charged as a capacitor, and if so, what difference in each plates properties may be observed? is plate distance by seperation a factor at all (in space).

v2 = u2+2as For the above equation, it was found by eliminating t from one of the below simultaneous equations, and substitute it into another euqation..... 1) v = at + u 2) s = ((v+u)/2)t where v = finally velocity a = acceleration t = time u = initial velocity s = displacement but who started this kind of equation? What kind of problem did this equation's inventor face upon which he forms this equation? I know it might be, because this equation contains much many information like acceleration, displacement, final/initial velocity, etc..., so it could much handy to use for solving problems, but however, if I see the equation alone, it makes no se…

I am a bit confused about the concept of magnets. It is said that magnets attract opposites, and repel likes. Now does that refer to the material, or a magnet being attracted/repelled by another magnet? Also... If an electromagnetic apparatus is strong enough, will attract/pull just about any type of matter? What are the conditions for a certain type of material to be pulled in by electromagnets? Thanks in advance. The reason I was wondering this is because I recently read Angels and Demons, and in it antimatter is created, kept in a vacuum sealed device, and is held by a group of powerful electromagnets. Althought it is a work of fiction, antimatter has …

Would just like a hint on how to start this pls. A particle P is attracted towards a fixed point O in an intertial frame by a force of magnitude [math]\lambda r^{-3}[/math] per unit mass where r=OP. The particle is set in motion at a distance a from O with speed v perpendicular to OP. b)If [math]\lambda >a^{2}v^{2}[/math] show that [math]u=r^{-1}=a^{-1}\cosh(\omega\theta)[/math] where [math]\omega[/math]should be determined , and that the particvle reaches O in time [math]\frac{a^2}{\sqrt(\lambda-a^{2}v^{2})}[/math] cheers

I am an 8th grade student who is interested in performing an experiment involving golf balls. My experiment would involve testing different kinds of balls to see which one goes the furthest. Keeping in mind that this is supposed to be a scientific experiment, I don't know how to hit the ball consistintly. The only thing that I could thing of was a swinging pendilum, put I wasn't sure if it would work. If you have any input at all, it would be very helpfull!

I just have to do a simple question using his third law. Can someone give me the sets of units that are compatible with the equation.. cos my data is given in days and meters.. and most of the stuff of the web says it should be in years and AUs whats the most convinient to do it?

Is there no process possible where the entropy of the universe decreases? If so, then what is the need of using the word spontaneous in the second law of thermodynamics? Why don't we just write any process? spacetime http://www.geocities.com/physics_all/index.html

Why do we use units(m/s) for velocity? Is it because if we don't, then the values are extremely small? If so, wouldn't not using units be good for doing ftl calculations? [math]1s=2.998x10^8m[/math] [math]X\frac{m}{s}=\frac{Xm}{s}=\frac{Xm}{2.998x10^8m}= \frac{X}{2.998x10^8}[/math]

Although this is a very simple question, I yet can't understand it. What is the difference between speed and velocity? I know that velocity has a direction, but what differnce does that make? Till now, I learn it off by heart, can anyone explain why does the velocity change as the direction changes?

I have a science teacher who's offered to help me out with airplane stuff since he know's that what I want to do. He's said we'll look into aerodynamics courses and the like at nearby colleges, maybe look for some nearby wind tunnels or something for some sort of internship. That's cool of him. He told me to think about projects I could do and so I've been thinking. There're a couple of possibilities I'd really like to look into, but would probably be too complex or too expensive (or both) for me to really manage. I was considering making a model (as in R/C, since I have a controller that could manage that right now) but that seems expensive and quite possibly a bit too …

here`s an interesting one. Imagine a transformer pluged into the main without a load on the secondary, it barely gets warm and will happily stay that way for days/weeks etc... now short out the secondary and it get quite hot quite fast, maybe even to the destruction of the device. now split the transformer into 2 halves, we have our primary plugged into the mains and it`s quite happy acting as a simple AC electromagnet why then should it get hot if I bring the other half (the shorted secondary coil) near to it? How does it "Know"? )

If I throw a stone(1 kg) upwards and the intial velocity is 14m/s, And Does that mean the acceleration is (14m/s)/s ? and the force is 14N? If so, how do i find out the time that I am exerting the force on the ball upwards? Secondly, I thought it must 1 second, because it never accelerates after intial volcity, and it is retarding due to the gravitational acceleration..... So what is the time I am exerting force on the ball upwards? Apreciate in advance Albert

I went sightseeing in a university. I went to the mechanical and engineering department. The day was an open day of the university , so there are some professors greet people and they show some particular small experiment or theory to us! I think I probably got into the mechanical and material engineering. They show some materials, aluminium, and an alloy of aluminium and copper. The professor told me that the alloy was very strong and is used for making aircraft. No one use a pure aluminium metal. He told me that it is strong because the copper added increased the resistance. The model of the alloy metal slides too but not for the whole row. Ya. That moment, I…