# Question #b01d3

##### 1 Answer
Jan 31, 2018

If balloon gains a charge of $- 8 \mu C$ then denim has gained a charge of $+ 8 \mu C$.

The force of attraction between them when they are separated by a distance of 5 cm is given as:

$F = \frac{1}{4 \cdot \pi \cdot {\epsilon}_{0}} \cdot \frac{{q}_{1} \cdot {q}_{2}}{r} ^ 2$

where,
${\epsilon}_{0} = 8.85 \cdot {10}^{-} 12 \frac{F}{m}$
(assuming there is air between the balloon and the denim)

${q}_{1} = - 8 \mu C$
${q}_{2} = + 8 \mu C$
$r = 5 \cdot {10}^{-} 2 m$

Substituting all the values in the equation we obtain force as,
-230.19 N. Negative value of F indicates the force is attractive in nature.