You have an infinite horizontal sheet of negative charge with surface charge density , as shown below. You wish to make a small metal sphere of mass m "levitate" in static equilibrium. You plan to give it a charge q such that the electric and gravitational forces on the sphere are in balance. (a) Where could you place a positively-charged sphere for it to be in static equilibrium? (Circle one; no explanation is required.) Above the sheet (positive y) Below the sheet (negative y) (b) Find an expression for the amount of charge q that will keep the charge in static equilibrium at the location you chose in part (a) above. Your answer could depend on , m, and any relevant physical constants