Two objects with charges Q1 and Q2 experience an electrical force of attraction of 8.0x10^-4 N when separated by a distance of d. Determine the force of attraction if the same objects are separated by:
a. a distance of 2d.
b. a distance of 3d.
c. a distance of 0.5d.
d. a distance of 2d and each object having double the charge.