A charge q of a mass m starts with a velocity vo in the +x direction. It passes the origin when an electric field of strength E pointing in the -x direction is switched on. (a) How far would the charge go before it comes to a stop? (b) Now let us say that instead of a constant E-field on the -x direction, that another charge q lies ahead of our moving charge at a distance a from the origin along the x-axis. Assuming that this charge is stationary, how far from the origin would it have to be to stop our moving charge in the same spot as part (a)?