Explanation:
The gravitational force exerted on an object by another is equal to that which the other exerts on it.
F=GMm/r²
G=6.67x10-¹¹Nm²/Kg²
r= 80cm=0.8m
F= [6.67x10-¹¹ x 70 x 55]/0.8²
F= 4 x 10^-7N.
