Question

Two copper spheres are currently 1.2 meters apart. one sphere has a charge of +2.2 × 10-4 c and the other has a charge of –8.9 × 10-4 c. what is the force between the charged spheres? is the force attractive or repulsive?

Answer 1

The force between two charged bodies is given by Coulomb's law:

$$F = k\dfrac{|q_1||q_2|}{r^2}$$

where $q_1 = 2.2\times 10^{-4}C$ and $q_2 = -8.9\times 10^{-4}C$ are the charges of the first and second body respectively, $r = 1.2m$ is the distance between the bodies, and $k\approx 9\times 10^9\space N\cdot m^2/C^2$ is Coulomb's constant.

Thus, obtain:

$$F =9\times 10^9\dfrac{| 2.2\times 10^{-4}|| -8.9\times 10^{-4}|}{1.2^2} \approx 1224\space N$$

Answer. 1224 N.