A 50000kg airplane starts from rest on the runway, takes off and reaches an altitude of 10000m and a speed of 550m/s, all in a time of 15.0min.
i. Assuming no thermal losses, what is the average power generated during this period?
ii. Assuming the average engine output was 1.5 times the power output of part (i), how much thermal energy loss?

Question

A 50000kg airplane starts from rest on the runway, takes off and reaches an altitude of 10000m and a speed of 550m/s, all in a time of 15.0min. 
i. Assuming no thermal losses, what is the average power generated during this period?
ii. Assuming the average engine output was 1.5 times the power output of part (i), how much thermal energy loss?

abhisar · Answer

Hello @Crystal997 !

We know that Power = Work done/Time.

Here the engine is providing work for two functions, the first is in attaining a height of $\sf 10^4$m and second in providing kinetic energy or speed of 550 m/s

abhisar · Answer

Right?

abhisar · Answer

So, we calculate the potential energy of plane by using the formula $\sf \boxed{P.E=mgH}$ and add it to the kinetic energy $\sf \Large({\frac{1}{2}}mv^2)$. This will give the total work done by the motor on airplane. We divide this work with the time taken and that will give us the power of plane.