# Why speed is required to stay in air?

## Main Question or Discussion Point

i want to say that when an aeroplane goes with highspeed,why the perpendicular gravitanional force is not acting on it and why does aeroplane dose not fall down perpendicularly??? plzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz reply 2 question as soon as possible..........

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Doc Al
Mentor
Gravity still acts on planes, but the air exerts an upward force on the plane that counters it. In a nutshell, the moving plane deflects air downward which creates an upward force on the plane.

cjl
Gravity acts on airplanes just as much as on anything else. However, the airplanes move fast enough that the forces on the airplane from the air are strong enough to balance out the gravity force.

Oh, and speed isn't required to stay in the air:

@doc can u explain it in more details..plzz....

i also want to know dat wat is stall speed?

When an aircraft moves forward its wings generate lift.

When lift > gravity the aircraft climbs, when lift < gravity the aircraft descends and when lift = gravity it flies at constant height.
i also want to know dat wat is stall speed?