FAA Ground School Practice Test

Which four forces are acting on an airplane during flight?

1. Lift, drag, thrust, and friction

2. Lift, thrust, drag, and weight

3. Lift, weight, power, and drag

4. Lift, weight, thrust, and pitch

The correct answer is: Lift, thrust, drag, and weight

The four forces acting on an airplane during flight are lift, thrust, drag, and weight. Lift is the force that opposes weight and is generated by the wings due to the airflow over them. This is crucial for an airplane to ascend and maintain altitude. Thrust is produced by engines and propels the airplane forward, overcoming drag. Drag is the aerodynamic resistance that acts opposite to the direction of flight, arising from the airplane moving through the air. Finally, weight is the gravitational force acting downward on the aircraft, counterbalancing lift. Understanding these forces is essential when studying flight dynamics, as they interact with one another to determine the flight path, stability, and overall performance of the aircraft. The correct identification of these four forces lays the foundation for deeper comprehension of aerodynamics and how aircraft generate lift, manage speed, and maneuver effectively. In contrast, some options incorrectly emphasize other concepts or forces not currently applied in aviation dynamics, such as friction or pitch, which don't directly describe the four fundamental forces impacting flight.