Question

Objects 1 and 2 attract each other with a electrostatic force of 18.0 units. If the distance separating Objects 1 and 2 is changed to one-third the original value, then the new electrostatic force will be _____ units.

Answer 1

Answer:

New force will become 162 units

Explanation:

Let the charge on each object is q and distance between then is r

Electrostatic force between to object is given by

$F=\frac{1}{4\pi \epsilon _0}\frac{q^2}{r^2}$

From the relation we can see that electrostatic force is inversely proportional to square of distance between them

Therefore $\frac{F_{new}}{F}=\frac{r^2}{r_{new}^2}$

Now  new distance $r_{new}=\frac{r}{3}$

So $\frac{F_{new}}{F}=\frac{r^2}{(\frac{r}{3})^2}$

$F_{new}=9F$

$F_{new}=9\times 18=162units$