1. Obj. 7.03 Transportation Systems (Air Transportation)

2. Four forces keep an airplane in the sky.

3. What is lift? Lift pushes the airplane up. The air moves around the wings giving the airplane lift. The shape of the wings helps with lift, too.

4. How does the shape of the wing help with lift? Airfoil Newton’s 1 st and 3 rd laws

5. Air comes straight at the wings, bends around it, and then leaves straight behind the wing. NO LIFT The air passes over the wing and is bent down. The bending of the air is the action. The reaction is the lift on the wing. LIFT

6. So… Wings provide lift by creating a situation where the pressure above the wing is lower than the pressure below the wing. Since the pressure below the wing is higher than the pressure above the wing, there is a net force upwards.

7. Weight Weight is the force that pulls the airplane towards Earth. Airplanes are built so that their weight is spread from front to back. This keeps the airplane balanced.

8. Thrust Thrust is the force that moves the airplane forward. Engines give thrust to airplanes. Sometimes an engine turns a propeller. Sometimes it is a jet engine. It doesn’t matter as long as air keeps going over the wings.

9. Drag Drag slows the airplane. You can feel drag when you walk against a strong wind. Airplanes are designed to let air pass around them with less drag.

10. An airplane flies when all four forces work together.