Two spheres have identical charges and are 75 cm apart. the force between them is +0.30 n. what is the magnitude of the charge on each sphere? (let x = charge) what can you tell about the charge signs on the spheres?

, charges are both positive or both negative

Explanation:

The electrostatic force between the two spheres is given by

where

k is the Coulomb's constant

q1 and q2 are the charges on the two spheres

r is the distance between the centres of the two spheres

In this problem, we have

is the force

is the distance between the spheres

because the two spheres have identical charge

Solving the formula for q, we find

And the two charges have the same sign (so, both positive or both negative), since the sign of the force is positive (+0.30 N), so it is a repulsive force.

the electric field is a “force field” around a charged object that illustrates the direction the electric force would push an imaginary 

no. dot product   =0 when vecs at right angles