about 7 miles per second. Which comes out to about 25000 mi/h which is about 40200 km/h.. oh...this is also neglegent of air friction so the actual number will be higher then this..here is the formula I used.


1/2 mv2 = GMm/R

 

this feels like a physics 30S review for me since im in the corse now

 

Brian, the problem with that formula is that the left side is an energy term, you'll get Newton*meters, and the right side gives a force, in newtons. Apparently I didn't get it right either, but I'm sure it'll have something to do with integrating the gravitational formula for "R". I like the energy equation too, it's a pretty nice shortcut to doing kinematics, but I do every problem in units first to make sure my numbers are gonna be right. Too bad I don't have my physics book, I'd look it up. TK

'77 F100, 302 (the aftermarket Prodigy), C4
Cadet Second Lieutenant John F. Daly III
South Carolina Corps of Cadets, The Citadel
The TorqueKing

 

TK...not once you simplify the formula..then you get the right units..the masses will cancel each other and you get the square root of 2gR...now that I started writing this I do see your point though...even the simplified version gives you m^2/s....now oyu really have me thinking

 

[updated:LAST EDITED ON 29-Oct-02 AT 00:21 AM (EST)]hint: Work == -Integral(Force.differential distance element) (This is a definite integral.)

edit: technical problems, i guess i didn't know HTML as well as i thought.

 

But what about when the birds are in the air and what if all the Chinese jump at the same time ? ;^)
Jim Henderson

 

>Hate to say this but: You're both wrong.
Time Out!

I have a picture of it in my physics book. tk gave the exact but if you take his answer and round it you get the answer that i gave.

Chris

P.S. No, i did not look in the book for the answer. I just pulled it out to confirm my answer.

 

>But what about when the birds are in the air and what if all
>the Chinese jump at the same time ? ;^)
>Jim Henderson


Hey, who said you could bring reality into this academia question? (HE, he, he... I was thinking the same thing. The weight changes all of the time. It is never fixed. Plus, Its weight is a purely philosophical (sp?) question anyway... because it really does just 'float' out there.... unless Earth actually lives on another planet than has the same gravity as Earth.)

 

My globe weighs about 1.5 lbs. and it 16" in diameter. So, if I multiply that by the actual diameter of the earth...

What is the airspeed velocity of an unlaiden sallow?

K.

 

Due to Heisenberg's uncertainty principle, it's correct to say that you cannot exactly calculate the actual mass of the earth, especially since the numbers we used to get it were approximations. They're very, very close approximations, but no number is quite perfect. The question is not theoretical, mass is constant throughout the universe. The principle of weight is however relative. The earth "wieghs" nothing in space, relative to somthing floating by, but it's mass is constant, as is the mass of everything in the universe. The only reason why you wiegh anything on earth is because of gravity, which is due to the tremendous mass of the earth and close distance to us. You weigh nothing in space because you're not close enough to a gigantic mass to have a significant gravitational force on you. Astronauts are not exactly wieghtless, they are in oribit. An orbit can be thought of as a freefall, but they're going so fast that they're falling towards the earth at the same rate that the earth is curving.

'77 F100, 302 (the aftermarket Prodigy), C4
Cadet Second Lieutenant John F. Daly III
South Carolina Corps of Cadets, The Citadel
The TorqueKing

 

As soon as I get on the scale, weigh myself, and subtract the difference of my weight without the world on my shoulders, I will let you all know!

Till then, don't hold your breath.

 

dont ask me why i remember this from science class but isnt the answer........ 6.6 sextillion tons?

 

[updated:LAST EDITED ON 29-Oct-02 AT 07:50 PM (EST)]Mass is not constant, that is a false statement believed up until the earlier part of the latter century, the total of E+M or Energy = Mass is constant as proven by Einstein's theory of relativity, E=MC^2. Mass can become energy and energy can become mass.

 

That's true, I was trying to over-simplify that to explain the difference between weight and mass. So not only are mass and weight relative, but so is mass, energy, and (gulp) time! There is nothing constant in the universe, all things are relative. This is why I'm a Civil Engineer, because I'm not dealing with astronomic quantities, and even though I know that I can never perfectly predict the bahavior of materials, or the loads we put on them, I know that I'm "Close enough for rock and roll", and if I'm not, then I'll just design something to be better than it has to be, just to be sure. Besides, here on earth, mass is always constant, until somebody sets off a nuclear bomb.

'77 F100, 302 (the aftermarket Prodigy), C4
Cadet Second Lieutenant John F. Daly III
South Carolina Corps of Cadets, The Citadel
The TorqueKing