Thrust
Thrust is the force of which pulls the object forward and creates speed to lift off.Thrust is the opposing force of drag. The source of thrust can be something like a propeller, a jet engine or even rocket engine and basically anything that can pull the object through the air.It can even be gravity, believe it or not gravity can be a source of thrust.
Drag
Drag is the opposing force of thrust.Drag is the force that creates a slowing affect to the object.
Gravity
gravity is the force that pulls the object to the ground, sending it earthwards . Gravity is the opposing force of lift.
Lift
lift is an important par in these 4 forces. Lift is the force in which is needed to keep the object in air. More is explained below.
As an airplane wing slices through the air it pushes air over its top and under its bottom surface .A wings curved shape is designed to cause air to move at a higher speed over its top surface compared to its bottom surface .A principle in physics states that faster moving air has lower pressure than slower moving air meaning that there is more pressure on the bottom surface of the wing than the top. The higher pressure air pushes up on the bottom of the wing and the result is lift. The angle of the wing relative to the air that it slices through, called ‘The Angle of Attack’, also contributes to the wings lift. A wing at a higher Angle of Attack generates more lift than a wing at a lower Angle of Attack. When a wing begins take off, its wing produces no lift because there’s no air flowing over it. However as the airplanes speed increases the wing generates more lift and when the pilot increases the airplane Angle of Attack the plane lifts of.