Acharged cloud system produces an electric field in the air near earth's surface. a particle of charge -2.0 × 10-9 c is acted on by a downward electrostatic force of 4.3 × 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?

Aparticle moves according to a law of motion s = f(t), 0 ≤ t ≤ 12, where t is measured in seconds and s in feet. f(t) = cos(πt/6) (a) find the velocity at time t (in ft/s).

You are given a vector a = 125i and an unknown vector b that is perpendicular to a. the cross-product of these two vectors is a × b = 98k. what is the y-component of vector b?

Balloon a has charge q, and identical mass balloon b has charge 10q. you hang them from threads near each other. choose all of the statements with which you agree. check all that apply. a. a and b exert the same magnitude forces on each other. b. the force that a exerts on b is 10 times the force that b exerts on a. c. the angle between the thread supporting a and the vertical is < the angle between the thread supporting b and the vertical. d. the force that a exerts on b is 1/10 the force that b exerts on a.