The equation F = arv + br2v2 gives the magnitude of the resistive force (in newtons) exerted on a sphere of radius r (in meters) by a stream of air moving at speed v (in meters per second), where a and b are constants with appropriate SI units. Suppose their numerical values are a = 3.40 10-4 and b = 0.780. Using this formula, find the terminal speed for water droplets falling under their own weight in air, taking the following values for the drop radii. (a) 10.0 µm (b) 100 µm (c) 1.00 mm. Note that for (a) and (c) you can obtain accurate answers without solving a quadratic equation, by considering which of the two contributions to the air resistance is dominant and ignoring the lesser contribution.