Question

A small sphere of mass m and charge +q with zero velocity falls under the influence of gravity (acceleration = g from height h onto an infinite uniformly charged plane with positive charge density sigma as shown below. What will the velocity of the sphere be when it hits the plane? Note that the electric field above an infinite plane of charge is constant everywhere, pointing away from the plane (for a positive charged plane) and equal to sigma/2*episilon . make the downward direction positive (acceleration due to gravity positive) and the repuslive electrostatic force up the negative direction