Atest charge is placed at a distance of 2.5 × 10-2 meters from a charge of 6.4 × 10-5 coulombs. what is the electric field at the test charge? (k = 9.0 × 109 newton·meter2/coulomb2)

The drag force, fd, imposed by the surrounding air on a vehicle moving with velocity v is given by fd = cdaρv 2/2 where cd is a constant called the drag coefficient, a is the projected frontal area of the vehicle, and ρ is the air density. an automobile is moving at v = 80 kilometers per hour with cd = 0.28, a = 2.3 m2, and ρ = 1.2 kg/m3.