Classical Physics

Chapter 13 part 4, Gravitational field of large objects, (page 13-8 in the commemorative edition) Just a foreword, I'm not trying to prove Feynman wrong and I'm expecting to be shown where my own judgement has let me down. I don't understand why Feynman has used p (roe, density) for the length if the mass per unit area is constant. I can see how length wise r^2=p^2+a^2, it's just pythagerous, but how can a length unit be equivalent to p, density? I don't understand. Whats more interesting is that when I use my own method of finding the field, I find exactly the same answer. Odd or what? Oh and if anyones wondering why I'm still studying the Feynman lectures even t…

Have you heard or known about "space wheel"?? It is a small wheel with 3 larger metal bits struck out in one dimension, and two cylindrical sticks coming out in another dimention horizontally, and is placed on a two-panel curved platform, which holds the wheel by the cylinderical sticks. The wheel just keeps rolling from one end of the platform to another, never stopping. WHat physics are involved?? it says three: 1) potential and kinetic energy, I know this one. 2) the law of thermodynamics 3) other mysterious forces I dont know 2) and 3) Any one?

I appologise if this is posted in the wrong section. I wasn't sure exactly where to post it. The Big Bang seems to be described as a black hole in reverse. Or at least it has in some of the books I've read. If this is the case, how come other black holes just fade away or evaporate? How come we havn't detected a similar explosion like that which supposedly created our Universe? Or am I missing a vital point?

Hi all I have some basic quations . 1 I read a report of news statation saying that space probes can never leave are solar seytem there are strange phononma that slows down anything tring to escape are solar seytem 2 What would happen if a comit came close to earth and affect the orbit of the earth and cause the earth to spin out of the orbit and spin out of are solar seytem in deep space and can NASA do anything to stop this or some how cause the earth to go back to its orbit 3.For aviation we use pellpeller ,jet egine and rockets in the future we may use Propulsion or antigravity how would this help aviation and NASA and are NASA working on any Propul…

a magnetic field is located north to south accross the z axis. a wire runs accross the x axis and is attatched to the source of the magnetism in such a way that the wire will not bend. a current is applied to the wire which makes a force on the y axis from the equation [imath]\mathbb{F}=\mathbb{B}{I}l[/imath]. if the wire cannot bend, will the force move the magnet as well or will it just try to bend the wire?

Here is copy of how radios work ..I still have some questions ---------- Trees and buildings affect radio waves as well as the weather. The sun can also affect radio waves; it can help the radio operator or cause problems. If the sun was gone the radio wave would still work. Why can a radio on the moon with a 5 inch antenna pick up NASA because NASA is transmitting at a very high power and using a very big antenna. How can NASA pick up radio transmissions coming from a portable radio on the moon using 3 watts; because NASA is using a big antenna and also a very good antenna. How can you transmit signals around the earth? Using HF sig…

Why does salt lower the temperature of Ice? My physics teacher said it did and its complicated so i should find out. Any idea?

I know that most thermocouples are used to measure temperature using the output voltage, but what about using the output voltage to do work? How much energy (%) can be had from a thermocouple?

I want to measure the distance to a mirror. I send a pulse of light to it and measure how long it takes for the round trip. I can then calculate the distance. While I'm waiting for the light to return am I correct in saying that the distance between myself and the mirror has no definite value?

http://www.phys.unsw.edu.au/~jw/sailing.html under the "How can boats sail faster than the wind? " section, it speaks about the relative wind speed. What is that??

is there a gauss's law for gravity? I mean that as an equivalent law that deals with gravity

Hi, I am currently having some problems in using a vernier callipers and screw gauge .I would appreciate a litle help in knowing how to calculate the measurement. PLEASE AND THANK YOU yours truly

How much calculus is needed for this book?

This question may seem simple but for a non-physicist like myself it is sometimes hard to grasp. I'm sure this is beginner's stuff. I have 2 guns, when fired the bullets leaves the barrel at the same speed relative to where I am standing. I put a target 100 yds away, mount one gun on a vehicle moving towards it and one gun stationary. The mounted gun is preset to fire at the target when it is 100 yds away and is synchronized with the firing of the stationary gun, also at the target. My feeling is that both bullets should hit the target at the same time.... is this correct?

Gravity is considered a misconception. Gravity really is the warping of space and time Explain, Elaborate Further and Debate.

I am curious... how accurately have we weighed things? Is there a point where the weight of an object will not stay still? To see this, I imagine, we would have to weigh something in grams to something like 20 decimal places and it would have to be somewhere completely devoid of vibrations. Is there an accuracy point where the weight is no longer fixed... where we would have to calculate the average weight rather than know the exact weight?

My buddy and I were in the car on our way to Best Buy when he had an interesting question. When you throw something up in the air in a moving object (in this case, a conversion van) it goes up into the air and lands relatively close to where you threw it up into the air. Why is this? Shouldn't the motion from the car moving force the ball backwards? Please explain as best you can. Thank you.

I have a question about photons. How can they have momentum but be massless. If they are massless, them they should have no momentum, and vice versa, right? p=mv. Or am I just applying classical mechanics laws to something I shouldn't?

If say a 1 tonne wieght and a coin were both dropped off a 100 meter tall building at the same time would they both hit the ground at the same time? If yes what is this law called? thanks

A friend just asked me how does wind affect the propagation of sound and I am ashamed to say I do not exactly know. It is experienced that when the wind blows from different directions, you would hear a distant sound differently. Obviously changes in pressure will affect some characteristics of the sound wave, but I cannot think of a model. Any ideas?

Does the specific heat capacity of an object affect the rate of transfer of energy from an object to another? For instance, alcohol has a lower specific heat capacity than water. If they are both at 50 degree Celsius and poured into a beaker containing water of 20 degree Celsius respectively, after 1 second, in which beaker, much heat is transferred? Thanks for kind attention.

I was doing a little thought experiment myself and thought maybe I could use some help. The rod here is an ideally rigid rod, and the tracks are of course frictionless and fixed. How does this configuration suspend itself up while gravity is pulling on it and there are no vertical forces to counter it? P.S. excuse my horrible paint skills again Additional Explanation: The two large circles are fixed tracks. The rod in the middle has two wheel rollers attached to it. Each roller is in one of the tracks. Because the rod is rigid, it won't allow the wheels to be separated anymore than they are. The red lines are just force vectors showing the tendency for movement…

ok, i've never taken a physics class before and have NO basic knowledge, so i was reading a book that mentioned maxwell's demon and how he just made up that thought experiment. well how can ppl just make up an experiment when they have no experimental evidence to support it?

A (rather large) space station is floating in Earth orbit, and maintains a 1-g artificial gravity by rotating a cylindrical section of the space station. Sound familiar? The classical sci-fi artificial gravity, using centrifugal force to push objects within to the outside walls of the station, which most of you have heard before. Now, given that hypothetical situation, what would happen if someone were to run in the opposite direction as the rotation? IE, the station is rotating clockwise and the runner is going CCW. Would this lessen the centrifugal force, and therefore the artificial gravity, placed upon the runner?

I noticed when I look very closely at just about any object with a curved surface with a straight line behind it running almost parallel to the edge but still intersecting it (or almost) that the line will bend toward the object as if the light is being attracted to it. we all know that the power of gravity is inversely proportional to the square of distance, so when you look very closely at the edge of a massive object, maybe the gravity from the mass of the object is actually strong enough to visually refract light due to the short distance? is this possible, or is this caused by some other Phenomenon? I know this takes place around super massive objects like black hole…