(a) How long would it take a 1.50×105 -kg airplane with engines that produce 100 MW of power to reach a speed of 250 m/s and an altitude of 12.0 km if air resistance were negligible? (b) If it actually takes 900 s, what is the power? (c) Given this power, what is the average force of air resistance if the airplane takes 1200 s? (Hint: You must find the distance the plane travels in 1200 s assuming constant acceleration.)

Problem 41PE

Solution 41 PE

Step 1:

In this question, we need to find time taken by airplane

In the second part , we need to find the power if time taken is

In the third part , with the power obtained in part two, we need to find average force of air

resistance if time taken is

Data given

Mass of airplane

Power

Final velocity

Height

Time taken

Time taken

Step 2 :

We shall find the work done by the airplane

It is given by

Substituting values we get

Step 3 :

We need to find time taken by airplane

This can be obtained using relation

Substituting values we get

Thus we have time taken as

Step 4 :

we need to find the power if time taken is

This can be obtained using relation

Substituting values we get

Hence the power required for 900 s is