Aircraft Motion

Question 1

For a body to be in a state of equilibrium there must be
[a] no motion occurring
[b] no force acting on the body
[c] no change in its motion
[d] the minimum amount of drag acting

Answer 1

C
When a body is in equilibrium all forces acting on it are balanced and no net force is succeeding
in producing any change in motion.

Question 2

The kinetic energy possessed by a moving body depends upon
[a] the velocity at which it is moving
[b] the total mass of the moving body
[c] the magnitude of the forces acting in the direction of motion
[d] both the mass and the velocity of the moving body

Answer 2

D
Kinetic energy = 1/2mv^2
It depends upon both the mass and the velocity .

Question 3

For an aircraft in level flight to cover the greatest distance per litre of fuel consumed it must be flown at a speed which
produces
[a] the least amount of drag
[b] the greatest amount of lift
[c] the lowest possible drag coefficient
[d] the lowest possible fuel flow

Answer 3

A
The work that can be done by a given amount of fuel is a product of the force and the distance.
Distance is greatest when force is least.

Question 4

For an aircraft to remain in the air for the greatest possible time per litre of fuel consumed, it must be flown at a speed
which requires
[a] the least amount of drag
[b] the smallest angle of attack
[c] the least amount of power
[d] the best lift/drag ratio

Answer 4

C
Power is a rate. It is proportional to fuel flow. The lower the fuel flow the greater the endurance.
Maximum endurance is achieved with minimum power.

Question 5

The net effect of all forces acting on an aerofoil can be attributed to a single imaginary force called
[a] lift
[b] the total reaction
[c] induced drag
[d] total drag

Answer 5

B
All of the forces produced by the various pressures acting on the aeroplane are resolved into the
total reaction.

Question 6

Indicated air speed is proportional to
[a] the angle of attack being used
[b] the density of the free airstream
[c] the kinetic energy of the free airstream
[d] the true outside air temperature

Answer 6

C
Indicated Air Speed, like kinetic energy depends upon both the velocity and the density of the air.

Question 7

For an aircraft to achieve maximum range in level flight in nil wind conditions it must be flown at a speed which
requires
[a] maximum thrust
[b] minimum thrust
[c] maximum power
[d] minimum power

Answer 7

B
Maximum range requires minimum drag. In level flight drag and thrust are equal, so minimum
drag is also minimum thrust.

Question 8

For an aircraft to achieve maximum endurance in level flight it must be flown at a speed which requires
[a] maximum thrust
[b] minimum thrust
[c] maximum power
[d] minimum power

Answer 8

D
Power is a rate. It is proportional to fuel flow. The lower the fuel flow the greater the endurance.
Maximum endurance is achieved with minimum power.

Question 9

The force of drag during flight always acts parallel to the
[a] thrust line
[b] wing chord
[c] longitudinal axis
[d] relative airflow

Answer 9

The total reaction is divided into two components, lift at right angles to the relative airflow and
drag, parallel to the relative airflow and opposite the direction of motion.

Question 10

To achieve maximum range in a piston engine aircraft, the power that is used must
[a] produce the lowest possible forward speed
[b] produce the indicated air speed corresponding to the highest lift coefficient
[c] produce the indicated air speed corresponding to the lowest lift coefficient
[d] produce the indicated air speed corresponding to minimum drag