Chapter 3, Problem 18STP

To determine

To Compare: The force that speeds up and slows down the airplane.

Explanation of Solution

Introduction:

The momentum of the airplane changes due to burning of fuel in the engine. This change in the momentum of the airplane exerts a force on the airplane. The exerted force acts opposite to the direction of air resistance.

If the force is greater than the air resistance, then the airplane starts moving in forward direction. The airplane speeds up or slows down due to more or less burning of the fuel in the engine. The amount of fuel burns control the change in the momentum. The variation in the momentum controls the exerted force on the airplane.

Conclusion:

Thus, the airplane speeds up or slows down due to change in momentum when fuel in the engine burns.