Calculate the charge on two identical spheres that are similarly charged if they are separated by 20cm and the electrostatic force between them is 0.006 N.

Explanation:

We know from theory that the magnitude of the force between two charges is measured by the expression

We know that two spheres have the same charge, and let's assume they're in a vacuum, so

At this point we can solve for Q

Double check calculations for safety, as usual

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.