Three paticles each of mass 100 gm are brought from a very large distance to the vertices of an equilateral triangle whose side is 20 cm in length. The work done will be

Options

A. `0 . 33 xx 10^(-11) J`
B. ` - 0.33 xx 10^(-11) J`
C. ` 1. 00 xx 10^(-11) J `
D. ` - 1.00 xx 10^(-11) J`

Answer

D

Explanation

Potential energy of three particles system ` U = (Gm_(1) m_(2))/(r_(1,2)) - (GM_(2) m_(3))/(r_(2,3)) - (GM_(1) m_(m))/(r_1,3) `
Given `m_(1) = m_(2) = m_(3) = 100 gm and r_(1,2) = r_(2,3) =r_(1,3) = 20 cm `
`:. U = - [(6 . 67 xx 10^(-11) xx 10^(-1) xx 10^(-1))/( 20 xx 10^(-2))] = - 1.00 xx 10^(-11) ` Joule