[Lucas]

Wow your smart! loll, your either a genius or you found this like dozens of other things on the internet! lol!

[cockerpunk]

functional question - should i add more to this, or do we have enough to talk about? do you guys want a thread like this? can you handle a thread like this without it going all crazy off topic?

[brycelarson]

cockerpunk, on Oct 13 2008, 07:17 PM, said:

functional question - should i add more to this, or do we have enough to talk about? do you guys want a thread like this? can you handle a thread like this without it going all crazy off topic?

I'm going to suggest that we lock this thread - anyone who has something physics related - please PM us and we'll add it to the initial post. That will keep relevant info at the top of the thread.

[Lord Odin]

I would at least recommend how to get Standard Deviation to the list as well. I think that's essential to a lot of our testing. Letting Excel do it is one convenient but it does nothing on implying the meaning or importance behind it.

[brycelarson]

I was thinking that a second thread about the basics of stats would cover that stuff.

[Lord Odin]

Ahh, ok. Cool.

Physics related, I would also include formulas related to gases, such as pressure.

[Captain Hollywood]

cockerpunk, on Oct 13 2008, 08:17 PM, said:

functional question - should i add more to this, or do we have enough to talk about? do you guys want a thread like this? can you handle a thread like this without it going all crazy off topic?

Yes! More! I personally am super interested in learning about this stuff, My teacher actually was suprised when she saw what I was reading. I say you should definitely do more on the subject.. As for the locking of the thread part, Not really nessesary unless some silly people come in here and make it super off topic in a bad way...

[cockerpunk]

ok, got some stats and other stuff in there.

[moyster14]

Ideal gas law maybe appropriate.

[cockerpunk]

moyster14, on Oct 14 2008, 02:54 PM, said:

Ideal gas law maybe appropriate.

yeah fluids stuff will be comming up.

[moyster14]

Coolness, that's were my weakness lies.

[chainsaw]

masspb, on Oct 10 2008, 10:26 AM, said:

you might want to give them gravity

g = 9.806 m/s

Im not trying to be too picky, but this seems like a crucial difference. The equation is actually:

g= 9.806 m/s²

The reason it is squared is because gravity is being measured as an acceleration not just as a speed.

[brycelarson]

chainsaw, on Oct 21 2008, 09:00 PM, said:

Im not trying to be too picky, but this seems like a crucial difference. The equation is actually:

g= 9.806 m/s²

The reason it is squared is because gravity is being measured as an acceleration not just as a speed.

isn't it more accuratly meters per second per second? not meters per second squared.

[pb101]

brycelarson, on Oct 21 2008, 10:12 PM, said:

isn't it more accuratly meters per second per second? not meters per second squared.

Yeah, but they mean the same thing. I would maybe put in power is measured in Watts. 1 hp = 746 watts.

If some of you kids are interesed in this stuff then I would suggest taking Physics.

[chainsaw]

brycelarson, on Oct 21 2008, 10:12 PM, said:

isn't it more accuratly meters per second per second? not meters per second squared.

Sorry if what I typed was confusing. When I said m/s² I meant, (m)/(s)² a.k.a. (m)/(s²) and (m)/[(s)(s)]. I didnt mean (m/s)². Again sorry for any confusion.

[brycelarson]

chainsaw, on Oct 21 2008, 10:00 PM, said:

Sorry if what I typed was confusing. When I said m/s² I meant, (m)/(s)² a.k.a. (m)/(s²) and (m)/[(s)(s)]. I didnt mean (m/s)². Again sorry for any confusion.

there we go - just wanted to clarify that for everyone.

[oerllikon]

Excellent write up. This is the jackpot of knowledge, for those who know how to use it to explain why certain things happen.
Judging by the teflon coefficients, wouldnt a J&J ceramic, or other barrel that has teflon in the bore, and a marballizer, for example(or other paint that has teflon on the shell), have a lot of a lower coefficient than a typical setup?

[pb4bean]

cocker punks my hero! go mechanical engineers in training!

[ikaneatmetal]

my mind. blown. im gonna have to reread most of that. curse me for not taking physics in highschool.

[Leftystrikesback]

cockerpunk, on Oct 11 2008, 08:16 AM, said:

no, surface area does not matter. again, this is the issue of applying the rules correctly.

the reason why the phone books do not come apart is not because there is a tremendous amount of surface area. if you look in the the formula for friction you can see why they are very hard to tear apart.

It's actually not that easy to see from the formula and I wasn't able to convince myself until I did a free body diagram. So I'm gonna take a stab at explaining it if that's OK with you. From the formula, the friction of the two phone books should be (u * W) where W is the weight of the phone book, since that's the force pushing down and u is the coefficient of friction for paper on paper. This does not equate to a whole lot of force, only about 10 pounds or so.

The explanation is as follows:
say there are 1000 pages in a phone book
each page lays on top of another, so the force for friction on the first page is the weight of that page times the coefficient of friction, lets say the weight of that page is 1/1000 of the total weight, W => weight = W/1000 and Friction = u*W/1000.
The weight on the second page is its own weight plus the weight of the pages above it, so the friction = u*2*W/1000.
and so on until you get the friction force on each page. So add up all those friction forces and what do you get?
Well you get a sum from 1 to 1000 times u*W/1000. The sum from 1 to 1000 = 1 +2+3+...+999+1000 = 500500.
So the total force from friction is 500*u*W.

lets say the coefficient of friction for paper on paper is .4 (just a guess, could be close though) and that the weight of a phone book is 15 pounds (just a guess) that means that the force it would take to pull the phone books apart is 500*.4*15 = 3000 pounds.

So surface area is not the reason for this large friction, its due to the fact that you add the friction from each page together, and that there are a lot of pages.