Bernouli's Principal

Question 1

Bernoulli’s principal is best described using
which effect?
a. Coriolis effect.
b. Venturi effect.
c. Neither a nor b

Answer 1

b. Venturi effect.

Question 2

Concerning the Venturi effect, as the crosssectional area of a tube is reduced, the
velocity of the airflow through the tube
must–
a. Decrease
b. Increase
c. Remain the same

Answer 2

b. Increase

Question 3

As the velocity of the air moving through a
venturi increases–
a. Static pressure decreases
b. Static pressure increses
c. Static pressure is difficult to measure and therefore an increase or decrease is considered neglible

Answer 3

a. Static pressure decreases

Question 4

Static pressure is defined as–
a. Compressed air containing positively
charged ions.
b. The atmospheric pressure of the air through which an airplane is flying.
c. The pressure

Answer 4

b. The atmospheric pressure of the air through which an airplane is flying.

Question 5

Dynamic pressure is defined as–
a. Compressed air containing positively
charged ions.
b. The atmospheric pressure of the air through which the airplane is moving.
c. The pressure of a fluid resulting from its motion.
d. None of the above.

Answer 5

c. The pressure of a fluid resulting from its motion.

Question 6

Relative wind is–
a. The air in motion that is equal and opposite the flight path velocity of the airfoil.
b. The angle measured between the resultant relative wind and the chord.
c. The angle between the airfoil chord line and
the longitudinal axis of the airplane.
d. None of the above.

Answer 6

a. The air in motion that is equal and opposite the flight path velocity of the airfoil.

Question 7

Angle of Attack is the angle measured between the resultant relative wind and the chord
a. True
b. False

Answer 7

a. True

Question 8

Center of Pressure is defined as:
a. The point along the mean camber line where all aerodynamic forces are considered to act.
b. The point along the chord line of an airfoil through which lift is considered to act.
c. The point along the chord line on an airfoil through which all aerodynamic forces are considered to act.

Answer 8

c. The point along the chord line on an airfoil through which all aerodynamic forces are considered to act.

Question 9

Aerodynamic center is the point along the chord line of an airfoil through which all aerodynamic forces are considered to act.
a. True
b. False

Answer 9

a. True

Question 10

Lift is defined as–
a. the component of the total aerodynamic
force that acts at right angles to drag.
b. the component of the total aerodynamic force that acts at right angles to the RRW.
c. Neither a nor b are true.

Answer 10

b. the component of the total aerodynamic force that acts at right angles to the RRW.

Question 11

The two factors that most affect the
coefficient of lift and the coefficient of drag
are:
a. weight & balance
b. thrust & air density
c. shape of the airfoil & angle of attack

Answer 11

c. shape of the airfoil & angle of attack

Question 12

Drag that is produced by non-lifting
portions of the airframe.

a. Form Drag
b. Parasitic Friction Drag
c. Parasitic Drag

Answer 12

c. Parasitic Drag

Question 13

The portion of drag that is generated because of the shape of the airplane.

a. Form Drag
b. Skin Friction Drag
c. Parasitic Form

Answer 13

a. Form Drag

Question 14

The boundary layer air creates lstagnant layer of air molecules.

a. Parasitic Drag
b. Skin-Friction Drag
c. Interference Drag

Answer 14

b. Skin-Friction Drag

Question 15

Created by the collision of airstreams. Causes eddy currents, restrictions, and turbulence to smooth flow.

a. Parasitic Drag
b. Skin-Friction Drag
c. Interference Drag

Answer 15

c. Interference Drag

Question 16

Drag created as a result of the production of lift. Creates wingtip vortices and vertical velocities.

a. Parasitic Drag
b. Induced Drag
c. Interference Drag

Answer 16

b. Induced Drag

Question 17

Varies inversely with the airspeed.

a. Parasitic Drag
b. Skin-Friction Drag
c. Interference Drag

Answer 17

c. Interference Drag

Question 18

Total drag is that component of the total aerodynamic force parallel to the
___________ that tends to retard the motion
of the aircraft.
a. chord line
b. center of pressure
c. relative wind
d. none of the above

Answer 18

c. relative wind

Question 19

An airfoil with a higher lift to drag ratio is
more efficient than an airfoil with a lower
lift to drag ratio.
a. True
b. False

Answer 19

a. True

Question 20

A stall occurs when:
a. The airplane enters the region of reverse command.
b. The airplane is flown above CL max.
c. The airfoil is flown at an angle of attack greater than that for maximum lift.
d. None of the above.

Answer 20

c. The airfoil is flown at an angle of attack greater than that for maximum lift.

Question 21

An aerodynamic stall occurs when an increase in the angle of attack results in a loss of lift and is due to:
a. low airspeed
b. density altitude
c. seperation of boundary-layer air.

Answer 21

c. seperation of boundary-layer air.

Question 22

When the boundary layer separates, turbulence occurs between the boundary layer and the surface
of the wing. This results in–
a. an increase in dynamic pressure above the wing.
b. an increase in the static pressure above the wing.
c. Neither a or b

Answer 22

b. an increase in the static pressure above the wing.

Question 23

Increasing the AOA beyond the boundary-layer separation point will result in–
a. a further increase in lift.
b. the boundary-layer separation point moving forward on the airfoil.
c. a decreased top surface area of the wing available to produce
d. b & c

Answer 23

d. b & c

Question 24

Designing the wing to stall from the
wingtips progressively inboard toward the
root section is a desirable airplane design
characteristic.
a. True
b. False

Answer 24

b. False

Question 25

Define Geometric Twist–
a. A method used to counteract torque.
b. That stupid lemon they always ruin your Corona with.
c. The twist of an airfoil having different geometric angles of attack at different spanwise locations.

Answer 25

c. The twist of an airfoil having different geometric angles of attack at different spanwise locations.