Question

A physicist found that a force of 0.68 n was measured between two charged spheres. the distance between the spheres was 1.0 m. calculate the force between the two spheres when the distance was decreased to 0.50 m.

Answer 1

The force between two system is inversely proportional to the square the distance between them. The indirect proportion between these items may be expressed as,
                                           F = k / d²
where k is the constant proportionality. Substituting the known values, 
                                     0.68 N = k / (1 m)²     ; k = 0.68
For the second case, 
                                     F = 0.68 / (0.5 m)² = 2.72 N
Thus, the answer is 2.72 N.