Quizzes at Fun Trivia Fun Trivia | quizzes Quizzes | games Games | community People | services Services | help Help | me Me
New Player - Log In
Currently 10948 players online.   Trivia games, quizzes, and contests - FREE !     Get Started! quiz register


  • New Questions

  • Unanswered

  • Revisited

  • Your Questions


  • Post a Question
  • Goto Qn #



    111,143 questions asked
    383,131 replies


    Archives

    Newton's law of gravitation is sometimes expressed by the equation - F = Gm1m2/d(squared) where F represents the force between two masses m1 and m2, d is the distance between centers of mass, and G is a constant. Is this a correct formulation of Newton's law of gravitation?

    Question #24026. Asked by Impress me.

    Gnomon

    Yes

    Nov 07 02, 8:02 AM
    Impress me

    No...Consider a carpenter's square with a point C an inch up and inside from where the two lines of the L intersect, and a point A a half inch further in from C. Now place a small spherical body at C. The distance between the center of mass of these two bodies, the sphere and the carpenter's square is zero! According to the statement of Newton's law of gravitation given in the question the attractive force between the two bodies would become infinite, which is clearly not the case. Indeed one may conclude that if the small sphere is placed at A the attractive force may tend to increase the distance between the center of the mass. Thus in terms of the statement of the law given in question the force becomes repulsive rather than attractive!

    Nov 07 02, 6:34 PM
    greencavalier

    Although the distance from the centrre of gravity is zero, the gravitational attraction is now coming from all around the little sphere, so it cannot be treated as if it is at the centre of gravity of the t-square.
    It is intersting that your weight is at a maximum at the earth's surface. If you go up in the air, or down a mine, you will weigh less. (But your mass will stay the same - sorry!)
    See this website:
    http://www.sciencenet.org.uk/database/Physics/0207/p01562d.html
    for a better explanation than I can manage.

    Nov 07 02, 7:08 PM
    Impress me

    Newton was well aware of the problem of determining the distance used in the formula for gravitational force. In his formulation the inverse-square law applies to mass particles rather than extended bodies, and the distance d is the distance between two mass particles. It is only in the special case of spheres whose densities are dependent only on the distance from their centers that d refers to the distance between their centers of mass, i.e., their geometrical centers.

    Nov 07 02, 10:04 PM

    Create a Free FunTrivia ID to add to, request more/new answers, or edit this entry

    Other Similar Questions & Answers


    Upon completion of high school, which two members of R.E.M. lived together in Macon, GA?

    Two bodies of masses M and m are raised to the same height above the floor, and released simultaneously. Assuming that the air resistance is constant and identical for the two bodies, will they reach the floor simultaneously?

    What is the link between actor Woody Harrelson and President John F. Kennedy?

    Between which two stations is the shortest distance on the London underground?

    Suggested Related FunTrivia Quizzes - 90,000 currently online

    1 In Between
    Lists abound. Can you put in the item that goes between the two given? Roy G Biv would know the answer to "In the spectrum: Between red and yellow" is orange.
    Thematic 10Q Tough Tough
    10 Q
    Dixie6256
    Oct 01 03
    1542 plays
    2 'M*A*S*H' - B. F. 'Hawkeye' Pierce
    Hawkeye is the central character around which the television show 'M*A*S*H' revolved, but what do you know of his life and times? This quiz will test you on that very topic...good luck!
    Benjamin Franklin 'Hawkeye' Pierce Average
    10 Q
    thejazzkickazz
    Aug 04 04
    6198 plays
    3 A "Gravitation" Who Am I?
    This is all about the characters from "Gravitation". The description will be given, then you provide the character matching that description. This quiz also goes by the subbed anime, so no manga or OVA are applied.
    G Average
    10 Q
    Toushirou
    Jul 29 09
    54 plays


    "Ask FunTrivia" is for entertainment purposes only, and answers offered are unverified and unchecked by FunTrivia. We cannot guarantee the accuracy or veracity of ANY statement posted. Feel free to post an updated response if you feel that an answer is inadequate or incorrect. Please thoroughly research items where accuracy is important to you using multiple reliable sources. By accessing our website, you agree to be bound by our terms of service.