question_answer

The velocity of an aeroplane is doubled. (a) What will happen to its momentum? Will the momentum remain conserved? (b) What will happen to its K.E.? Will the energy remain conserved?

Answer:

                (a) when the velocity of the aeroplane is doubled, its momentum also gets doubled. However, the combined momentum of aeroplane + air is conserved. As the momentum of the aeroplane increases, the momentum of air also increases by an equal amount in the opposite direction. (b) The kinetic energy becomes four times. The additional energy is obtained by burning of fuel. However, the total energy is still conserved.