Answer:
400 N
Step-by-step explanation:
From the question,
F = kmm'/r²........................ Equation 1
Where F = gravitation force, m and m' = mass 1 and mass 2 respectively, r = distance between the masses.
Given; F = 800 N
Substitute these values into equation 1
800 = kmm'/r².............. Equation 2
If the distance is doubled (2r), and one of the mass is doubled (2m), The new force is
F' = k(2m)(m')/(2r)²
F' = 2kmm'/4r²
F' = kmm'/2r²................. Equation 3
Comparing equation 2 and equation 3
F' = F/2............................ Equation 4
Substitute the value of F into equation 4
F' = 800/2
F' = 400 N