# The Four Forces Of Flight

## The Four Forces.

If lift becomes greater than weight, then the plane will accelerate upward.

If the weight is greater than the lift, then the plane will accelerate downward.

When the thrust becomes greater than the drag, the plane will accelerate forward.

If drag becomes greater than the thrust a deceleration will occur.

Maintaining a steady flight requires balance.

## Weight (Force 1)

(Definition)

Weight is the force of gravity. It acts in a downward direction towards the center of the Earth.

## Lift (Force 2)

(Definition)

Lift is the force that acts at a right angle to the direction of motion through the air. Lift is created by differences in air pressure

## Thrust (Force 3)

(Definition)

Thrust is the force that propels a flying machine in the direction of motion. Engines produce thrust.

## Drag (Force 4)

(Definition)

Drag is the force that acts opposite to the direction of motion. Drag is caused by friction and differences in air pressure.