Answer: The gravitational force when the masses are doubled is 400 N
Step-by-step explanation:
To calculate the gravitational forces, we use the equation:

Where,
F = gravitational force
G = Universal gravitational constant
= mass of object 1
= mass of object 2
r = distance between the objects
When F = 100 N, the equation becomes:

When the masses of bot the objects are doubles, the equation becomes:

Hence, the gravitational force when the masses are doubled is 400 N