# Two charges of  -3 C  and  2 C  are at points  (-9,3,8)  and  ( 3,-6,7), respectively. Assuming that both coordinates are in meters, what is the force between the two points?

Feb 11, 2016

$F \cong - 0 , 239 \cdot {10}^{9} N \text{ Force is attractive}$

#### Explanation:

$\text{distance between(-9,3,8) and (3,-6,7):}$
${r}^{2} = {\left(3 - \left(- 9\right)\right)}^{2} + {\left(- 6 - 3\right)}^{2} + {\left(7 - 8\right)}^{2}$
${r}^{2} = 144 + 81 + 1$
${r}^{2} = 226$
$\text{force between two charges is given by Coulomb's law:}$
$F = \frac{k \cdot {q}_{1} \cdot {q}_{2}}{{r}^{2}}$
$F = \frac{9 \cdot {10}^{9} \cdot \left(- 3\right) \cdot 2}{226}$
$F = \frac{- 54 \cdot {10}^{9}}{226}$
$F \cong - 0 , 239 \cdot {10}^{9} N \text{ Force is attractive}$