A pigeon in flight experiences a force of air resistance given approximately by F = bv2, where

Question:

A pigeon in flight experiences a force of air resistance given approximately by F = bv2, where v is the flight speed and b is a constant.
(a) What are the units of the constant b?
(b) What is the greatest possible speed of the pigeon if its maximum power output is P?
(c) By what factor does the greatest possible speed increase if the maximum power is doubled?