Charge q1 = -7.5 nC is located at the coordinate system origin, while charge q2 = -1.92 nC is located at (a, 0), where a = 1.3 m. The point P has coordinates (a, b), where b = 0.95 m. A third charge q3 = 13.5 nC will be placed later.

Arailroad car collides with and sticks to an identical railroad car that is initially at rest. after the collision, the total kinetic energy of the two cars is a) the same as before. b) half as much as before. c) one third as much as before. d) one fourth as much as before. e) twice as much as before.