The speed of an airplane doubles in flight. (a) how is the law of conservation of momentum obeyed in this situation? (b) the law of conservation of energy?

a) The law of conservation of momentum is satisfied because there must be air (and other combustion byproducts) expelled behind the aircraft as it moves forward. The collective momentum of those gases is equal in magnitude and opposite in direction to the forward momentum of the aircraft. b) The aircraft obeys conservation of energy because it is simply converting energy to different forms. In its stationary form, there existed latent chemical energy in both the fuel on board and the oxygen in the air. As the aircraft moves, some of that chemical energy is converted into kinetic energy and heat, but it is indeed conserved.