Answer
(a) The hummingbird needs to do 0.070 J to 0.175 J of work with each wingbeat.
(b) A human-powered aircraft with flapping wings would not seem possible for extended periods of time.
Work Step by Step
(a) Birds needs to produce 10 W to 25 W per kg.
Since the hummingbird flaps its wings 10 times per second, the hummingbird needs to do 1 J to 2.5 J of work (per kg) with each wingbeat.
Since the mass of the hummingbird is 0.070 kg, we can multiply the work per kg by 0.070 kg. The hummingbird needs to do 0.070 J to 0.175 J of work with each wingbeat.
(b) To produce 10 W to 25 W of power per kilogram, a 70-kg athlete needs to produce 700 W to 1750 W of power. Since the steady power output of a 70-kg athlete is only 500 W, a human-powered aircraft with flapping wings would not seem possible for extended periods of time.
