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Homework Help: Gravitational force?

  1. Feb 4, 2015 #1
    1. The problem statement, all variables and given/known data
    1)Find the gravitational force between then sun (2*10^30 kg) and the earth (5.97*10^24 kg). Earths distance from the sun is 1.5 * 10^11m.

    2) find the distance between a 5 kg object and a 10kg object if their gravitational force is 1*10^-4N.

    2. Relevant equations
    Fg= (G(m1)(m2))/r^2

    3. The attempt at a solution
    1) (6.67*10^-11)(5.97*10^24)(10)(5)/(1.5*10^11)^2= 3.50*10^22

    2) (6.67*10^-11)(10)(5)(1*10^-4)/r^2=
    √3.33*10^-13 =r^2

    So... 5.77*10^-7

    Yes... these "answers" may look chaotic which is why I am here for some assistance. :/
  2. jcsd
  3. Feb 4, 2015 #2
    In doing question 1, where is the mass of the earth in the equation? What are the 10 and the 5 doing in the equation?
    In doing question 2, the 1*10^-4 should be on the other side of the equation.

  4. Feb 4, 2015 #3


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    Staff Emeritus
    Science Advisor
    Homework Helper

    Where is the mass of the sun in the equation above?
    Where are the units of your answer?

    What is the factor 10-4 for?
    What are the units of G?
    You need to state the units with your answers, otherwise your calculations are incomplete and ambiguous.
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