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Homework Help: I'm in need of help on my physics

  1. Feb 16, 2008 #1
    Could anyone help me with these problems? It's on Gravitational Force

    The drawing shows three particles far away from any other objects and located on a straight line. The masses of these particles are mA = 363 kg, mB = 517 kg, and mC = 154 kg. Find the magnitude and direction of the net gravitational force acting on each of the three particles (let the direction to the right be positive).
    particle A N
    particle B N
    particle C N

    A bowling ball (mass = 7.2 kg, radius = 0.10 m) and a billiard ball (mass = 0.32 kg, radius = 0.028 m) may each be treated as uniform spheres. What is the magnitude of the maximum gravitational force that each can exert on the other?
  2. jcsd
  3. Feb 17, 2008 #2
    The fact that the 3 masses are far away from any other object imples that only the 3 masses are interacting with each other via the gravitational force. You can treat them as uniform spheres, which means that they are point particles located at the sphere's center with mass M. So, what is the equation that you are going to use ?

  4. Feb 17, 2008 #3
    Start from the basic and use this for a system of two particles separated by distance r.

    use... G*m1*m2/r^2

    Now see that 3 particles can create 3 pairs.Be careful with the distance between a and c and the sign notation when moving from c to a and from b to a.
  5. Feb 17, 2008 #4
    so what ima do is...6.67*10^-11(363kg)(517kg)/9.8^2....or is that not right?
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