For example, if it takes 60 watts of Power for a machine to fly, yet loses (for instance) 2.5 * 10^3 Joules of its energy because of the air resistance, whats the amount of "Power" that was really given in the first place? The time of flight for the machine is 30 minutes to get to the height of 2230 meters. Any suggestions or tips? I've been stumped by this problem for a while now. Thanks.