Question

Two point masses each equal to $1kg$ attract one another with a force of ${10}^{-9}kgwt$. Find the distance between the two point masses. Take: $g=9.8m/s^2$.

• A. $8cm$
• B. $0.8cm$
• C. $80cm$
• D. $0.08cm$

Answer 1

The correct option is A $8cm$

$F=\frac{G{m}_1{m}_2}{r^2}$
$\therefore r^2=\frac{G{m}_1{m}_2}{F}$

or, $r=\sqrt{\frac{G{m}_1{m}_2}{F}}=\sqrt{\frac{6.6\times {10}^{-11}\times 1\times 1}{9.8\times {10}^{-9}}}$
or, $r=8cm$