Classical Physics

Can someone explain the rocket equation to me in as much detail as they are capable of? Thank you

A thought has been coming to me lately. The title of this thread doesn't mean a frame in which the speed of light is c. It has to do more with the work of Mach. In an otherwise empty universe, how can you tell whether or not something is spinning? Also Newton's bucket has been on my mind. Also the principle of equivalence has been on my mind. But what has really been on my mind is Galileo's law of inertia, or if you prefer, Newton's first law of motion. Postulate 1: Somewhere in the universe is the center of mass of the universe. Ok so postulate one asserts the existence of a preferred location in space, a special place in the universe. …

Suppose that we have two enormous spheres, and let each of them be a rigid body. Let one be the size of the earth, but far more dense, and let the other be the size of the moon, and also much more dense. Now, let them be touching, the smaller one on top of the bigger one. Would gravity cause the smaller one to start rolling around the bigger sphere, or would it just sit on top?

Let's analyze the case of a rigid body, say a paralelepiped (a x b x c), which presents a certain temperature distribution U(x,y,z) in the stationery state (the distribution doesn't change over time). We can keep the lower face to a certain temperature u, and the other 5 faces at zero degrees, in whatever temp units you like. Then, Fourier's law of heat transfer says: dU/dt (1/c^2) = div(grad U) ; which can be simplified as div(grad U) = 0, since ?U/?t = 0 By solving (using separation of variables) this equation, we obtain: U(x,y,z) = (16u/pi^2)Sum[ Sum[ (1/mn)(sinh(q*(c - z))/sinh(q*c)) sin(m?x/a) sin(n?y/b) ] ] ; You can see "Mathematical Physics…

I was thinking of how to represent this on a graph with (0,0) being the source of the wave. After some though I came up with: y=x^2*y^2*t*(w-Vsin[theta])+x^2*y^2(Vsin[theta]-w) t= time w= speed of wave in the medium v= velocity [theta]= angle taken at right angle to motion counter clockwise. This is probably wrong but I can't find it on google and got too bogged down to think it through again.

another general question.... if you have an object in space (ie. a spaceship) and you want it to orbit nearby planets, can you do it by taking the centre of mass of the 2 planets. Cheers guys (i hope this thread is in the right place ) Sarah

hey everyone sorry i just got back from a big night out last night and yeah hard to think, so that sort of explains the title anyways.... my query (this is not a homework question of anything, just a general th0ouoght i had when reading a physics text) why is it that when a pendulum is swinging that you can assume it has maximum KE at the bottom of its swinging arc? Cheers Sarah

I long ago encountered a question which I have never seriously discussed with anyone at length, and I wish to do so now. Suppose that there is a way that some hollow shell object could be constructed so that Newton's third law is untrue to travellers inside of it, if the object is accelerated. For definiteness, let the object accelerate by emitting a massive amount of virtual photons. The idea is to be that the ship emits particles which follow F=ma, in the frame, but there is no reaction force on the ship. If the object starts off in space in a frame where v=0 and W=0, and then accelerates to g in that frame, and then maintains that acceleration, what would …

how is heat transmitted through a vacuum? If heat is the vibration of particles, then how can it travel through no medium? When heat is transmitted through particles, is it transmitted by infared light?

http://www.geocities.com/thesciencefiles/singleslit/diffraction.html] Refer to this web site, please. The brightness of the colour is proportional to its amplitude? I can understand why the middle of the screen is the brightest, but in my mind, I think there should be only one area which is bright for a single-slit. Is that light has many beams and able to create interference for even only a single-slit? The diffraction of a light beam is really different from that of a water wave, isn't it?

Suppose you have a spinning object rotating in a cylinder propelled from the bottom and sides by magnets and have no friction. If you spun the object, and then let it spin forever without any air, static, rolling, or sliding friction, would the object spin forever, or would the magnets have an electromagnetic friction that would cease the object to move eventually? Note: the object spinning would be given an initial force but from then on no other forces are applied except from the magenets. Thanks.

I just heard there is physics olympiad in this country (I'm talkin' about US). But I'm not sure what do you do or other stuffs.. I heard first round is multiple choice exam for 40 min and then second round for open question and then sending to "real" olympiad.. Can anyone tell me more about it? Thanks.

Long ago, I was talking with Tom Mattson about something, and he asked me what I meant, and I never did finish explaining to him what I meant. Part of what I said was, that I operationally defined the binary relation 'before,' on the set of moments in time. Since I didn't finish then, I will now. An operational definition is a non-verbal experiment which somehow assigns meaning to some term. The term here is 'before' A little thought, and you will see that if you are an adherent to "absolute time" and "absolute simultaneity," that before is a binary relation on the set of moments in time. At any rate... Suppose you go to the moon, and drop two …

Someone said that if you throw a magnet around (presumably against hard surfaces) the magnet will begin to lose its magnetism... the impact effects the magnetic domains or something... Is this true?

If you dig a hole in the earth and jump there, the gravity pulls you down right? This is a hypothetic situation and I know it cant be duplicated but lets assume for a moment that you can dig a hole deep enough to go through the whole earth. You jump in that huge hole and the gravity will continue pulling you until you get to the center of the earth or what? Will you be suspended in the center or just continue falling until you get to the other side and then start falling again or what?

If there was a hole straight through the earth and (neglecting all other effects that would prohibit doing this) and someone jumped into it, would you after passing through the centre point start to bungy back and forth untill coming to a rest right at the centre due to gravity? What would happen?

I have a question about Mach's theory of sound. I am not sure how much it influenced Albert Einstein. Mach did an analysis of some kind, and figured out that if you could ever reach the speed of sound in air, that there would be some kind of cone thing going on. From what I briefly read, the Mach equations used v/c, where v was the speed of the object in the medium, and c was the speed of sound in the medium. Einstein was a Mach fan... the v/c term, I think what Einstein did was basically apply the Mach equations to the speed of light. Einstein knew that light was a wave from Maxwell's EM theory, and for einstein the vacuum was a fluid to light, just like ai…

I list the question one by one. I hope this is a good arrangment. 1.The blades of a fan is rotating in an anti-clockwise direction. Its motion is frozen with a strobe frquency of 1000 Hz without a change in appearance. Which of the following is not a possible rate at which the wheel is rotating? There are six slits on the fan. A.200 revolution per second. B.500 rev. per second. C.2000 revolution per second. 2.Why the wavelength of a wave increase when it passes from a shallow region to a deep region? Does the amplitude change? 3.Why the wavelength of a wave increase when it passes from a shallow region to a deep region? Does the amplitude change? 4. Why does the w…

i got a question, if i spin rapidly a 2kg book on my fingers, why does it seem to be lighter than when its stationary??

While reading this article on Foucalt pendulum I came across this: Is that a true statement, that an inertial reference frame is one in which the coriolis and centrifugal forces vanish? I would like to discuss this at length. Thank you

Suppose I want to measure the mass of the moon in the following way. I want to do a handstand on the moon. Suppose that the moon is a perfect sphere, and that it has a uniform density. Will it matter where on the moon I do the handstand? Let us suppose that I have an excellent "muscle memory" and that I remember how hard it is to do a handstand on earth. Define the earth to have one inertial mass unit. I go to the moon, do my handstand, and go wow, that was 1/3 easier therefore [math] M_{moon} = \frac{1}{3} M_{earth} [/math] So that the moon has a mass of 1/3 imu The question really has to do with the vacuum, not the moon, nor my method of …

here's a question i want some confirming on: Alice, Bob, Charlie and Daniel are standing on the edge of a canyon which is 100m deep and 20m wide. On the opposite side of the canyon, there is a 10m high cave, 15m below the top of the cliff. They want to see who can throw a rock horizontally and get it into the cave. They each throw a rock with the following initial velocites: Alice 5m/s, Bob 10m/s, Charlie 15m/s and Daniel 20m/s. Whose rock makes it into the cave? I got an initial velocity of 5.12 m/s so therefore alice's rock will make it. Did any1 else get this answer as well? if not, can you tell me the answer you got instead? thanx

Just a quick question, something i've been wondering about... Do gravity waves carry information? And if so, what information? Is it mass\size\density\distrance from observer\? Also, how does this apply to the event horizons of black holes? Essentially don't you still receive gravity waves of objects beyond the event horizon, before they reach the singularity? I'm probably an idiot and just rambling of things i have no grasp on though

There will be no waves for the transerve wave any more after a period of time, why? Disturbance is added, it starts to move. Where does the energy lose? Why do the particles always try to archieve at their equilibrium level(position)?I can understand the energy loss in longitudinal wave but not transverse wave. Please explain it to me. Water wave can be transerve wave and longitudinal wave, right? What happens if the energy is not totally lost? It rebounds? Why do the particles always try to archieve at their equilibrium level(position)?

I just read this site: Deductive proof of Newton's third law Look where he says: Fnet = ma, tells us that the net (vector sum) of all forces acting on a body is equal to the product of the body's mass and its vector acceleration. I think the verbal formulation of this is wrong. Draw a circle. Then pick a point on the circumference. Draw the tangent line. Draw the normal line. If a force F is applied along the normal line, then all of that force will go into translating the object, because the force is aimed right at the center of mass. But suppose the contact force isn't along that line, suppose that the angle of incidence is [math] \theta [/…