Three particles each of mass m are placed at the comers of an equilateral triangle of side , d. Calculate
work done on this system if the side of the triangle is changed from d to 2d

Explanation

When d is changed to 2d, `U_(B) = - (3 Gm^(2))/( 2d)`
So, work done `= U_(B) - U_(A) = (3 G m^(2))/(2d)`