Physics

[Gunn]

I know some of you will laugh at me for this but i'm really interested and have a ton of questions. I was a history buff in school and didn’t care to much for physics or anything else that dealt with math because I suck at math. Basically what I wanted to know is do any of you know or have advanced knowledge of physics or know someone who does. I am asking here because I tried to email a professor at a local college and he won’t answer me back so I have no clue how to ask some questions I have. Also if you have any ideas on good sites on the web that aren’t filled with crap I would like to know them. I say good sites because that’s where I began my search and to tell you the truth there is a lot of bullshit on the web and I cant seem to get heads or tails from it because I don’t know physics so I cant quantify if the numbers are even nominally correct or if they are bunk. So if you can help please let me know.

[Frendab]

Try http://www.howstuffworks.com or if you can't find what you want there then try here http://en.wikipedia.org/wiki/Physics

[Junniper]

What are the questions? Maybe some of us science program dropouts can give you useful information.

[Gunn]

Basically my questions concern mainly magnets and loss of magnetism. The next question would be strength and distance of strength of the magnets. Also I want to know the lifespan of magnets if they are in constant contact with other magnets. Other questions as far as physics are concerned are how does friction actually calculate into loss of momentum and how is the conversion of movement put to power such as in the way windmills create power. As far as power production I want to know how much force it takes to create energy and also basically a table that shows force to power output. I will stop with that I have a lot more questions but that will do for now.

[Antilikos]

Quantum, Newtonian, or Astro?

A place I have found alot of interesting articles is in Scientific American.

http://www.sciam.com/channel.cfm?chanID=sa026&catID=2

Some of it is way over my head, but there are some really interesting things they write about along with alot of additional references if you want more.

Anti

[Junniper]

Basically my questions concern mainly magnets and loss of magnetism. The next question would be strength and distance of strength of the magnets. Also I want to know the lifespan of magnets if they are in constant contact with other magnets.

The lifespan thing depends entirely on what type of alloy they are.

That's all I can give up for magnets.

Other questions as far as physics are concerned are how does friction actually calculate into loss of momentum and how is the conversion of movement put to power such as in the way windmills create power. As far as power production I want to know how much force it takes to create energy and also basically a table that shows force to power output. I will stop with that I have a lot more questions but that will do for now.

You would want to research power generators first to match a specific power requirement, THEN research windmill energy to match your power generator.

So the amount of force required would depend entirely on how much power you needed to produce and what kind of generator you were using.

here is what wikipedia has to say about Friction:

The classical approximation of the force of friction known as Coulomb friction (named after Charles-Augustin de Coulomb) is expressed as:

Ff = uN

Where:

u is the coefficient of friction,
N is the normal force to the contact surface,
Ff is the maximum possible force exerted by friction.

This force is exerted in the direction opposite the object's motion,thus it is an opposing force.
This law mathematically follows from the fact that contacting surfaces have atomically close contacts only over extremely small fraction of their overall surface area, and this contact area is proportional to load (until saturation which takes place when all area is in atomic contact thus no further increase of friction force takes place).
This simple (although incomplete) representation of friction is adequate for the analysis of many physical systems.


Here is a clip from wikipedia on wind power:

The power in the wind can be extracted by allowing it to blow past moving wings that exert torque on a rotor. The amount of power transferred is directly proportional to the density of the air, the area swept out by the rotor, and the cube of the wind speed.
The power P available in the wind is given by:



The mass flow of air that travels through the swept area of a wind turbine varies with the wind speed and air density. As an example, on a cool 15°C (59°F) day at sea level, air density is 1.225 kilograms per cubic metre. An 8 m/s breeze blowing through a 100 meter diameter rotor would move almost 77,000 kilograms of air per second through the swept area.
The kinetic energy of a given mass varies with the square of its velocity. Because the mass flow increases linearly with the wind speed, the wind energy available to a wind turbine increases as the cube of the wind speed. The power of the example breeze above through the example rotor would be about 2.5 megawatts.

[Killtacular]

My brain hurts.

[Atelo]

My brain hurts.

Well that doesn't take much to start with

[Gunn]

Junn that was a big help. I will have some really cool diagrams soon for you all so you know why i was asking all thease questions.

[Gunn]

Actualy i came up with another question here, i was wondering if there is any way to turn electrical current into thrust?

BTW ive found this so far and it is very cool
http://www.thespacesite.com/space_elect ... lsion.html