Unit 4 Exam

Which best describes Newton’s Third Law of Motion?

• Any object will remain at rest until an force acts on it.

• For every action there is an equal and opposite reaction.

• Any object will remain in motion until an force acts on it.

• Any force applied to an object moves the object in the same direction of the force.

The reaction of downwash causes an downward reaction according to Newton’s Third Law of Motion.

• True

• False

Which of the following is true for an airplane in steady flight? Select all that apply.

• The sum of all upward components of forces equals the sum of all downward components of forces

• The sum of all forward components of forces is greater than the sum of all backward components of forces

• The sum of all upward components of forces equals the sum of all forward components of forces

• The sum of all forward components of forces is greater than the sum of all downward components of forces

• The sum of all forward components of forces equals the sum of all backward components of forces

Which of the following is true relative to a changing angle of attack?

• decrease in angle of attack will increase the pressure below the wing and increase drag

• An increase in angle of attack will decrease the pressure above the wing and increase lift

• An increase in angle of attack will increase the pressure above the wing and increase drag

• An decrease in angle of attack will increase lift

The Longer Path theory (or Equal Transit Time theory) says that the molecules of air flowing over the top of a wing must travel faster than the molecules of air flowing beneath the wing in order to meet at the trailing (back) edge. What is the problem with this theory?

• It assumes that molecules of air arriving at the front of the wing are divided equally above and below the wing.

• It assumes that molecules move at the same speed regardless of how fast air flows above and below the wing.

• It assumes that molecules of air arriving at the front of the wing at the same time must also arrive at the back edge of the wing at the same time.

• It assumes that more air travels above the wing than below the wing.

The _________ of an airplane can act as an airfoil by helping to produce stability and lift.

• propeller

• fuselage

• vertical stabilizer

• all of these

Increasing an airplane’s wing area will . Select all that apply.

• reduce pressure below the wing
• increase drag

• increase lift

• increase the camber

If the velocity of an airplane is doubled, the lift will .

• increase by a factor of 2

• increase by a factor of 4
• decrease by a factor of 4

• decrease by a factor of 2

An aircraft always stalls at the same regardless of airspeed, weight, or any other factor. (4.B.4)

• velocity

• angle of attack
• altitude

• acceleration

Considering an aircraft's weight and balance, is the term used to describe the line or reference plane from which all measurements of “arm” are taken. (4.C.1)

• moment

• station

• datum
• center of gravity (CG)