A proton is projected into a uniform electric field that points vertically upward and has magnitude E. The initial velocity of the proton has a magnitude U0 and is directed at an angle a below the horizontal.
(a) Find the maximum distance hmax that the proton descends vertically below its initial elevation. You can ignore gravitational forces.
(b) After what horizontal distance d does the proton return to its original elevation?
(c) Sketch the trajectory of the proton.
(d) Find the numerical values of hmax and d if E = 500 N/C. U0 = 4.00 X 105 m/s, and a = 30.0o.