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Gravity and mass of two objects

  • Thread starter AnkhUNC
  • Start date
  • #1
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Homework Statement


There are two masses of unknown weight on a straight line with a small red particle between them. At x (Measured from the center of m1) = .515 the particle does not move. What is the ratio of the two masses? i.e. m2/m1.


Homework Equations





The Attempt at a Solution



So do I use F = G*m1*m2/r^2? Since the particle isn't moving then the forces are balanced does this mean F = 0 then?
 

Answers and Replies

  • #2
tiny-tim
Science Advisor
Homework Helper
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Hi AnkhUNC! :smile:
So do I use F = G*m1*m2/r^2?
Not exactly … you use F1 = G*m*m1/r1^2 and F2 = G*m*m2/r2^2 and F1 = F2.

Hint: what is the relationship between m1/m2 and r1/r2? :smile:
 
  • #3
91
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On the right side the min x = .043 on the left side the max is .957. It starts out at .5 though which is in the middle so I guess <- is 0 and -> is 1.

r1/r2 = 1, they're both .5 away so .5/.5 = 1.

m2 is greater than m1 because the attraction is stronger so does m2 = .515 and m1 = .485?
 
  • #4
91
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So F = G*m*m1*m2?
 
  • #5
tiny-tim
Science Advisor
Homework Helper
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249
On the right side the min x = .043 on the left side the max is .957. It starts out at .5 though which is in the middle so I guess <- is 0 and -> is 1.
Sorry, AnkhUNC, but I honestly have no idea what this means. :confused: :cry:
F1 = G*m*m1/r1^2 and F2 = G*m*m2/r2^2 and F1 = F2.
Hint: divide F1 by F2. :smile:
 
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