Two small plastic spheres each have a mass of 1.2 g and a charge of - 56.0 nC. They are placed 3.0 cm apart (center to center). Part A What is the magnitude of the electric force on each sphere? Express your answer to two significant figures and include the appropriate units.

F_e = + / - 0.013133 N

Explanation:

Given:

- charge on each sphere q = - 56 nC

- separation of spheres r = 3.0 cm

- charge constant k = 8.99*10^9

Find:

- Magnitude of Electric Force F_e on each sphere.

Solution:

The magnitude of electric Force F_e of one sphere on other is:

F_e = k*q^2 / r^2

- Plugging the given values:

F_e = (8.99*10^9) * (56*10^-19) ^2 / (0.03) ^2

F_e = 0.013133 N

- An equal and opposite force is experienced on the other sphere. Hence, F_e = + / - 0.013133 N