Question

1.Two point charges, Q_A = +8 μC and Q_B = -5 μC, are separated by a distance r = 10 cm. What is the magnitude of the electric force? The constant k = 8.988 x 10⁹ Nm²/C

2.Two charged particles Q_P = +10 μC and Q_q = +20 μC are separated by a distance r = 10 cm along the horizontal. What is the magnitude of the electrostatic force?

Answer 1

The Coulomb's law says

$$F=k\frac{q_1q_2}{r^2}$$

1.

$$F_1=9*10^9*\frac{8*10^{-6}*5*10^{-6}}{(0.1)^2}=36\:\rm N$$

2.

$$F_2=9*10^9*\frac{10*10^{-6}*20*10^{-6}}{(0.1)^2}=180\:\rm N$$