Two chargess `+q` and `+2q` , are held in place on the x axis at the locations x`= -d` and `x= +d` respectively. A third charge, `+3q` , is released from rest on the y axis at `y = d`. (a) Find the electric potential at the initial location of the third charge. (b) Find the initial electric potential energy of the third charge. (c) What is the kinetic energy of the third charge when it has moved infinity far away from the other two charges ?

Explanation

(a)`V= K (q)/(dsqrt(2)) + K(2q)/( d sqrt(2))= ( 3 Kq)/( d sqrt(2))`
`= ( 1)/( 4pi epsilon_(0)) ( 3q)/( dsqrt(2))`
(b)` U = ( 3q) V`
`= (1)/( 4piepsilon_(0)) ( 3q)/( d sqrt(2))`