Question

Four particles, each of mass m, are placed at the four corners of a square of side 'a'. Force exerted by this system on another particle of mass m placed at the midpoint of a side of square is -

• A. $\frac{16G{m}^2}{5\sqrt{5a^2}}$
• B. $\frac{16G{m}^2}{5\sqrt{3a^2}}$
• C. $\frac{16G{m}^2}{5a}$
• D. zero

Answer 1

The correct option is D zero

$F_A=\frac{Gm\cdot m}{a^2}$

$=\frac{24m^2}{a}$

$F_c=\frac{4m\cdot m}{a^2}=\frac{24m^2}{a}$

$F_c=F_A\&F_B=F_A$

So, all are equal and opp. so zero