Electric force?

Question

Calculate the electric force that exists between two objects that are 7.3 × 10–2 m apart and carry charges of 4.5 × 10–6 C and –7.2 × 10–6 C. Is this force attractive or repulsive?

Answer 1

F = k * q1 * q2 / r^2 = (9 x 10^9)(4.5 x 10^-6)(-7.2 x 10^-6) / (7.3 x 10^-2)^2 N = -54.72 N

 

It is attractive (opposite charges attract)