Two electrons, each with mass m and charge q, are released from positions very far from each other. With respect to a certain reference frame, electron a has initial nonzero speed v toward electron b in the positive x direction, and electron b has initial speed 3v toward electron a in the negative x direction. The electrons move directly toward each other along the x axis (very hard to do with real electrons). As the electrons approach each other, they slow due to their electric repulsion. This repulsion eventually pushes them away from each other.