Posted by Lynda on .
Force of attraction between two spheres is 3.75 x 10^5 dyne when the spheres are placed 18 cm apart. What is force of attraction when placed 52 cm apart?

Math Ratios 
Reiny,
F = k (1/d^2) , where F is the force, d is the distance between them , and k is a constant
for the given:
3.75x10^5 = k/18^2
k = .01215
so F = .01215/d^2
when d = 52
F = .01215/2704 = appr 4.50x10^6
or
F1/F2 = (d2/d1)^2
F1/3.75x10^5 = 18^2/52^2
F1 = 4.50x10^6