Physics of Flight

Why should a pilot fly at a different airspeed for any given angle of attack to maintain lift in higher altitudes?

• The air is more dense

• The air is less dense

• The air is warmer

• The air is more humid

What do you need to do to maintain lift on a humid day in the middle of summer compared with a dry day in the middle of winter?

• nothing

• fly at a lesser velocity

• fly at a greater velocity

• decrease your angle of attack

Why is weight always directed toward the center of Earth?

• because of the force of acceleration

• because of the force of gravity

• because of the force of lift

• because of the friction of drag

What is NOT an aerodynamic force?

• lift

• drag

• weight

• mechanical

What is a gravitational force?

• lift

• weight

• drag

• thrust

What would cause an aircraft to decelerate until its airspeed no longer provides enough lift to support the plane in the air?

• Drag is less than thrust

• Thrust and drag are equal

• Thrust is less than drag

• Weight is greater than drag and thrust

Why does a pilot need to keep his or he angle of attack fairly high during low speed flights? A greater angle of attack:

• generates a lift force equal to the aircraft's weight

• increases thrust and airspeed

• balances lift and thrust

• increases airspeed

What type of drag concerns air stickiness and the boundary layer?

• skin friction drag

• interference drag

• form drag

• viscosity drag

What type of drag does balanced flight always include?

• form

• induced

• interference

• skin friction

How do vortices produce induced drag?

• Air Flows above the tip and comes back in a downwash behind the wing, pulling down and back on the aircraft

• A greater air pressure is created on the wing tops than on the bottom

• Air passes over an aircraft's parts, hits one of these objects, then rejoins when it gets to the other side

• Airplane surfaces meet at sharp angles, creating different air currents that collide and create drag