A negative charge of −7.0×10–4 C and a positive charge of 7.0×10–4 C are separated by 0.75 m. What is the force between the two charges?

A negative charge of −9.0×10–6 C exerts an attractive force of -80 N on a second charge that is 0.5 m away. What is the magnitude of the second charge?

F=k q1q2/r^2    k= 8.99 x10^9

Substituting results in:

F= - 783.13 x 10^1 N

   = - 7831.3 N           Since the result is NEGATIVE the force is one of ATTRACTION