To solve this problem we will apply the concepts related to the Electrostatic Force given by Coulomb's law. This force can be mathematically described as
[tex]F = \frac{kq_1q_2}{d^2}[/tex]
Here
k = Coulomb's Constant
[tex]q_{1,2} =[/tex] Charge of each object
d = Distance
Our values are given as,
[tex]q_1 = 1 \mu C[/tex]
[tex]q_2 = 6 \mu C[/tex]
d = 1 m
[tex]k = 9*10^9 Nm^2/C^2[/tex]
a) The electric force on charge [tex]q_2[/tex] is
[tex]F_{12} = \frac{ (9*10^9 Nm^2/C^2)(1*10^{-6} C)(6*10^{-6} C)}{(1 m)^2}[/tex]
[tex]F_{12} = 54 mN[/tex]
Force is positive i.e. repulsive
b) As the force exerted on [tex]q_2[/tex] will be equal to that act on [tex]q_1[/tex],
[tex]F_{21} = F_{12}[/tex]
[tex]F_{21} = 54 mN[/tex]
Force is positive i.e. repulsive
c) If [tex]q_2 = -6 \mu C[/tex], a negative sign will be introduced into the expression above i.e.
[tex]F_{12} = \frac{(9*10^9 Nm^2/C^2)(1*10^{-6} C)(-6*10^{-6} C)}{(1 m)^{2}}[/tex]
[tex]F_{12} = F_{21} = -54 mN[/tex]
Force is negative i.e. attractive
