What makes gravity stronger and weaker

Discussion in 'Physics & Math' started by want to learn, Apr 23, 2006.

  1. want to learn Registered Member

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    22
    What makes gravity stronger and weaker?
    Is there a formula to calculate gravity?

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    I would like to know the strength of the gravity on earth and the moon.
     
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  3. cato less hate, more science Registered Senior Member

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    2,959
    F=G*M*m/(r^2)

    where F is the force, G is the universal gravitational constant (6.67300 × 10^-11 m^3 kg^-1 s^-2), M is the mass of the first body (say the earth), and m is the mass of the second body (say, you), and r is the distance between the two masses.

    it can get more complicated than that, but that is the basics.

    so, if one or both of the masses decrease, the force will be smaller. also, the force weakens as the masses mover farther apart.
     
    Last edited: Apr 23, 2006
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  5. Pete It's not rocket surgery Registered Senior Member

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    Strictly speaking, cato's formula is for point masses.

    But, (luckily for us!) it so happens that the attraction between small masses and large spherical masses (like planets and moons) follows the same formula, where r is the distance between the centers of the two masses.

    You can find the masses and sizes of the Earth and Moon using our friend Google

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  7. want to learn Registered Member

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    thanks for the formula but i don't know what ^ means can someone help me.
     
  8. Facial Valued Senior Member

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    2,225
    It means the number following it is an exponent.

    4^2 would be 16, for example.
     
  9. Pete It's not rocket surgery Registered Senior Member

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    10,167
    It means "raise to the power of".

    So,
    F=G*M*m/(r^2)

    Means:
    F = G M m / r²

    Here it is at Hyperphysics, which has a built-in calculator for you

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  10. want to learn Registered Member

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    o thank you i never knew that
     
  11. want to learn Registered Member

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    i bet no one knows this 8^1/3=?
     
  12. cato less hate, more science Registered Senior Member

    Messages:
    2,959
    well, do you mean 8^(1/3) or (8^1)/3?

    and the cube root of 8, is 2. anyone who has taken a digital systems class (all engineering majors) would know that off the top of their heads.
     
  13. Facial Valued Senior Member

    Messages:
    2,225
    Or maybe just high school, period.
     
  14. want to learn Registered Member

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    i am learning that for advanced math for my grade i am 2 years ahead then my class can someone teach me hard math questions and how to answer them.
    but i bet u can't get this (100,000,000^1/7)
     
  15. cato less hate, more science Registered Senior Member

    Messages:
    2,959
    well, yes, anyone who has gone over powers in school would be able to figure that out pretty quickly. I simply meant that someone who has taken digital systems would have that instantaneously.
     
  16. cato less hate, more science Registered Senior Member

    Messages:
    2,959
    hard math question? that's pretty vague. if you want to know something about exponents, algebra, geometry/trigonometry, ect ask a specific question, and someone might help.

    however, you don't really need to come here for that kind of math. it is explained well on many sites. you can use our friend google to find them.
     
  17. przyk squishy Valued Senior Member

    Messages:
    3,203
    Or anyone with a general interest in IT. When I was 14 I knew all the powers of 2 by heart up to 2^16, + 2^24, simply because I saw them come up so often. I imagine this is the case for a lot of technically minded people.
     
    Last edited: Apr 26, 2006
  18. przyk squishy Valued Senior Member

    Messages:
    3,203
    13.89495494373137637129985217353011622113046714491000204945628679031600242410316581384175638975421432388192326614908053250190898074127381395990119970142975307347090762824400952540377876368704800799779013144115337840331897299066676688203504749868129984320253700038200643307774811195500481429323084739802622698361042631929020360689904124657509064176112077955391772635954006134982624589949405564877159569167756506502214740313606029267399516887708316111568731525272328672623139652182471025561201011231801778591164849344257891709923998725076732841310970535050400577841702182348352815144871583731739411378582483774397875371171974954620475713175667332597296359463897028138422255096095436544907470607322687346479911697691295139217812186091033615889985906960057117070006698888661987797435833083126506432734361257405690949432405959697151617467288678424332933857401287777336693825911806237718281825168015229568265967434751109627238727043515194623030347902983103461118974159234225628474721378047312190891094166349...

    You think we can't use calculators? :bugeye:
     
  19. przyk squishy Valued Senior Member

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    3,203
    If you meant 10,000,000<sup><sup>1</sup>/<sub>7</sub></sup> instead of 100,000,000<sup><sup>1</sup>/<sub>7</sub></sup>, the answer's:

    10.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000...

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  20. want to learn Registered Member

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    I am sorry for the mistake the real question is 100,000,000^1/8
     

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