This chapter starts out talking about aerodynamics which is the motion of air and the forces that act on things moving through the air. During flight there are 4 forces acting on a plane. Lift is the upward force created when air passes over and under the wing. Lift is what keeps the plane in the sky. Weight is the opposite of lift and is caused by the pull of gravity. Thrust is the forward force which pushes the airplane through the air. Thrust depends on the amount of engine power used. The opposite of thrust is drag. Drag is the backward force which limits the speed of an airplane. In unaccelerated flight, the four forces are in balance. Unaccelerated flight means the airplane is going at a constant speed and not accelerating or decelerating.
When the forces are shown with arrows they are called vectors. I'm glad I took physics last year because it made this section easy to understand. I already know a lot about vectors and Newton's laws of force and motion. What did know was Bernoulli's Principle which says "as the velocity of air increases its internal pressure decreases." This means when air flows through a tube which is narrower in the middle, it speeds up through the narrow section.
The chapter goes on to talk about airfoils which is any surface like a plane wing that reacts with a moving stream of air. Why the plane flies, stalls, wing design factors, and pilots control over these things are explained. Ground effect is described;when you are flying close to the ground the earth's surface actually changes the airflow pattern around a airplane and pilots need to learn how to deal with that. All and all section A was very interesting.
