Question

The centers of two 15.0 kg spheres are separated by 3.00 m. The magnitude of the gravitational force between the two spheres is approximately what?
A) 1.11 × 10^-10 N
B) 3.34 × 10^-10 N
C) 1.67 × 10^-9 N
D) 5.00 × 10^-9 N

Answer 1

 we have to use newtons law of gravitation which is
F=GMm/r^2 
G=6.67 x 10^-11N kg^2/m^2
M=(15kg)
m=15 kg
r=(3.0m)^2 
putting values we have 
=(6.67 x 10^-11N kg^2/m^2)(15kg)(15kg)/(3.0m)^2 
=1.67 x 10^-9N