Answer:
[tex]7.2 \times 10 {}^{11} newton[/tex]
Explanation:
[tex]the \: magnitude \: of \: the \: forc \: e \: can \: be \: calculated \: using \: coulombs \: formular \\ f = \frac{k \times q1 \times q2}{d {}^{2} } \\ f = \frac{9 \times 10 {}^{9} \times 100 \times 20 }{5 {}^{2} } \\ f = \frac{18000 \times 10 {}^{9} }{25 } \\ f = \frac{18000000000000}{25} \\ f = 7.2 \times 10 {}^{11} newton[/tex]