A passenger weighing 70 kg sits in the seat of an aircraft flying at a speed of 720 km / h. Find the kinetic energy of the passenger

| April 25, 2021 | education

A passenger weighing 70 kg sits in the seat of an aircraft flying at a speed of 720 km / h. Find the kinetic energy of the passenger: a) in the frame of reference associated with the aircraft b) in the frame of reference associated with the Earth.

a) In the frame of reference associated with the aircraft, the kinetic energy Ek = 0, since the passenger sits motionless in the seat of the aircraft (V = 0, Ek = (m * V ^ 2) / 2 = (m * 0 ^ 2) / 2 = 0).
b) In the frame of reference associated with the Earth, we calculate the kinetic energy by the formula:
Ek = (m * V ^ 2) / 2, where m is the mass of the passenger (m = 70 kg), V is the speed of the passenger together with the aircraft relative to the Earth (V = 720 km / h = 720 * 1000/3600 = 200 m / from).
Ek = (m * V ^ 2) / 2 = 70 * (200 ^ 2) / 2 = 1400000 J = 1.4 MJ.
Answer. a) Ek = 0, b) Ek = 1.4 MJ.



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