Two point charges, each of mass m and charge q are released when they are at a distance d from each other. What is the speed of each charged particle when they are at a distance 2r ?

Explanation

According to momentum conservation, both the charge particles will move with same speed. Now applying energy conservation :
`0+0+(Kq^(2))/r=2 1/2 mv^(2)+(Kq^(2))/(2r) implies v=sqrt((Kq^(2))/(2rm))`