Identical 50 μc charges are fixed on an x axis at x = ±3.0 m. a particle of charge q = -15 μc is then released from rest at a point on the positive part of the y axis. due to the symmetry of the situation, the particle moves along the y axis and has kinetic energy 1.2 j as it passes through the point x = 0, y = 4.0 m. (a) what is the kinetic energy of the particle as it passes through the origin? (b) at what negative value of y will the particle momentarily stop?