Two objects have a gravitational force of 800 N. If they are moved twice as far apart and the mass of one object doubles, what is the new gravitational force?

400 N

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

we need to know the time interval during which the force acts. impulse of force = momentum change