A charged cloud system produces an electric field in the air near Earth's surface. A particle of charge -1.7 x 10-9 C is acted on by a downward electrostatic force of 3.0 x 10-6 N when placed in this field.
(a) What is the magnitude of the electric field?
(b) What is the magnitude of the electrostatic force on a proton placed in this field?
(c) What is the gravitational force on the proton?
(d) What is the ratio of the electrostatic force to the gravitational force in this case?