iÂ·deÂ·a. n. 1. Something, such as a thought or conception, that is the product of mental activity. 2. An opinion, conviction, or principle: has some strange political ideas. 3. A plan, purpose, or goal: She started school with the idea of becoming a doctor. 4.
The direction of the thrust is normally along the longitudinal axis of the rocket through the rocket center of gravity. But on some rockets, the exhaust nozzle and the thrust direction can be rotated, or gimbaled. The rocket can then be maneuvered by using the torque about the center of gravity. The magnitude of the thrust can be determined by the general thrust equation.
A plane's ability to get off the ground depends on four main forces and how they interact with each other. These four forces are thrust, drag, lift, and weight. Thrust is the force created by the plane's engine that pushes it forward. It is similar to the force of a car's engine pushing the car down the road. Drag is the force of the wind pushing back on the plane. Airplanes must contend with the force of drag whether or not it is a windy day because, even on a still day, the effect of air movement is created as the plane flies through the air. Drag pushes the plane in the opposite direction from the direction of thrust.