Answer :
Given :
Charge on human 1 , [tex]q_1=2\ C[/tex] .
Charge on human 2 , [tex]q_2=-2\ C[/tex] .
Force of attraction between them , F = 650 N .
To Find :
Force between them , F =- 650 N .( force between opposite charge is -ve )
Solution :
We know , electrostatics force between two charge is given by :
[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]
Here k is universal gravitational constant , [tex]k=6.67408 \times 10^{-11}\ m^3\ kg^{-1}\ s^{-2}[/tex] .
Putting all given value in above equation we get :
[tex]-650=\dfrac{6.67408 \times 10^{-11}\times 2\times (-2)}{r^2}\\\\r=\sqrt{\dfrac{6.67\times 10^{-11}\times 2\times 2}{650}}\\\\r=6.40\times 10^{-7}\ m[/tex]
Hence , this is the required solution .