Three paticles each of mass 100 gm are brought from a very large distance to the vertices of an equilater
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_(3))/(r_(1" "3))`
Given `m_(1)=m_(2)=m_(3)=100` gm and `r_(1" "2)=r_(2" "3)=r_(1" "3)=20" cm"`
`therefore U=-3[(6.67 xx 10^(-11) xx 10^(-1) xx 10^(-1))/(20 xx 10^(-2))]` =- `1.00 xx 10^(-11)"Joule"`