# Two charges of  -3 C  and  -2 C  are at points  (0,-1,8)  and  ( -2,4,7), respectively. Assuming that both coordinates are in meters, what is the force between the two points?

Mar 6, 2016

$F = 1 , {8.10}^{9} \text{ N}$

#### Explanation:

$\text{The Point of A :} \left(0 , - 1 , 8\right)$
$\text{The Point of B :} \left(- 2 , 4 , 7\right)$
$\text{distance between the point A and B:}$
$\Delta r = \sqrt{{\left(- 2 - 0\right)}^{2} + {\left(4 + 1\right)}^{2} + {\left(7 - 8\right)}^{2}}$
$\Delta r = \sqrt{4 + 25 + 1} \text{ } \Delta r = \sqrt{30} m$
${r}^{2} = 30$
$\text{The Electrical Force between two charges acting each other is given as:}$
$F = k \cdot \frac{{q}_{1} \cdot {q}_{2}}{r} ^ 2$
$F = \frac{9 \cdot {10}^{9} \cdot \left(- 3\right) \cdot \left(- 2\right)}{30}$
$F = \frac{6 \cdot 9 \cdot {10}^{9}}{30}$
$F = 1 , {8.10}^{9} \text{ N}$