P Post-test 4 (Aircraft Structures & Design)

1. Distributed loads can be represented by:

A. A distributed force

B. A system of forces

C. A single force

D. None of the above

A. A distributed force

B. A system of forces

2. What are the three conditions for static equilibrium?

A. All of the above.

B. The sum of all moments acting on a body must be zero.

C. The body must not be accelerating.

D. The sum of all forces acting on a body must be zero.

A. All of the above.

3. Which load case is critical for the design of aircraft fuselage frames?

A. Cabin pressurization loads

B. Engine thrust loads

C. Taxiing loads

D. Crosswind loads

A. Cabin pressurization loads

4. A 600 N force is applied to a lever at a distance of 0.5 meters from the pivot point. If the lever has a mechanical advantage of 4, what is the force at the other end of the lever?

A. 150 N

B. 1,200 N

C. 75 N

D. 2,400 N

B. 1,200 N

5. When sizing a turbofan engine for a multi-engine military transport aircraft, which operational requirement typically establishes the absolute minimum required thrust loading on a constraint diagram?

A. Climb gradient requirement

B. Maximum cruise speed at optimum altitude

C. Loiter endurance time in a holding pattern

D. Maximum landing field length on wet runways

A. Climb gradient requirement

6. An unswept laminar wing profile has a critical Mach number of 0.7. Applying simple wing sweep theory, what is the estimated effective critical Mach number if the wing is given a leading edge sweepback angle of 30 degrees?

A. 0.606

B. 0.933

C. 0.808

D. 0.75

C. 0.808

7. Passenger access doors are normally located in the ______ of the airplane C.G.

A. Top

B. Front

C. Bottom

D. Aft

B. Front

8. Aircraft landing gears are designed to primarily withstand:

A. Tensile loads

B. Shear loads

C. Bending loads

D. Compressive loads

D. Compressive loads

9. A thin-walled single-cell rectangular box girder representing a wing spar has dimensions h=0.4 m and b=0.2 m, with a uniform skin thickness t=2.5 mm. If an applied torque of 20 kN⋅m acts on the cross-section, what is the resulting shear stress in the skin?

A. 50 MPa

B. 25 MPa

C. 100 MPa

D. 12.5 MPa

A. 50 MPa

10. How does the position of the centroid change if the shape is stretched or scaled uniformly?

A. The centroid remains unchanged

B. The centroid moves closer to the center of the shape

C. The centroid moves away from the center of the shape

D. The centroid moves in a random direction

A. The centroid remains unchanged

11. What is the moment of inertia of a uniform disk about an axis passing through its center of mass and perpendicular to its plane?

A. 1/2 MR^2

B. MR^2

C. 1/6 MR^2

D. 1/4 MR^2

A. 1/2 MR^2

12. This control surface is responsible for rolling.

A. rudder

B. spoiler

C. elevator

D. aileron

D. aileron

13. What is the relationship between stress and strain in an elastic material?

A. They are not related to each other.

B. They are directly proportional to each other.

C. They are inversely proportional to each other.

D. They have a non-linear relationship.

B. They are directly proportional to each other.

14. In a cabin air recirculation system, recirculated air and fresh air are supplied in the proportions.

A. 70% of fresh air, 30% of recirculated air.

B. 50% of fresh air, 50% of recirculated air.

C. 60% of fresh air, 40% of recirculated air.

D. 40% of fresh air, 60% of recirculated air.

C. 60% of fresh air, 40% of recirculated air.

15. For what purposes are NAVs typically used?

A. Long-range surveillance

B. Radar confusion

C. High-altitude reconnaissance

D. Payload delivery

B. Radar confusion

16. The centroid of a composite figure is determined by:

A. Finding the center point of each individual component of the figure

B. Choosing a point arbitrarily within the figure

C. Finding the average of the coordinates of all the points in the figure

D. Dividing the figure into simpler shapes and finding the centroid of each shape

D. Dividing the figure into simpler shapes and finding the centroid of each shape

17. What is the purpose of the empennage in an aircraft?

A. To control the aircraft's attitude and stability

B. To store fuel

C. To house the engines

D. To provide aerodynamic lift

A. To control the aircraft's attitude and stability

18. Loads X, Y and Z are placed -100 in, -75 in, and 50 in from the datum. If X = 750 and Y = 200, how heavy is load Z?

A. 4,000 lb

B. 800 lb

C. 1800 kg

D. 800 kg

D. 800 kg

19. How much CG change for fixed-wing aircraft is considered negligible?

A. less than 1% MAC

B. less than 0.1% MAC

C. less than 0.5% MAC

D. between 0.5% to 1% MAC

C. less than 0.5% MAC

20. A particle is moving in a circle with a radius of 10 meters. If its tangential velocity is 20 m/s, what are the radial and transverse components of its acceleration?

A. Radial = 20 m/s², Transverse = 10 m/s²

B. Radial = 20 m/s², Transverse = 0 m/s²

C. Radial = 0 m/s², Transverse = 20 m/s²

D. Radial = 10 m/s², Transverse = 20 m/s²

B. Radial = 20 m/s², Transverse = 0 m/s²

21. What are the consequences of exceeding the maximum design loads on control surfaces?

A. Control surfaces become inoperable

B. The aircraft loses stability and control

C. Control surface deflections become limited

D. Control surface loads are redistributed to other components

B. The aircraft loses stability and control

22. The centroid of a triangle is related to its medians in the following way:

A. The centroid lies on each median but not necessarily at its midpoint

B. The centroid is the midpoint of each median

C. The centroid is not related to the medians of a triangle

D. The centroid divides each median into two segments of equal length

A. The centroid lies on each median but not necessarily at its midpoint

23. What type of structural instability occurs when a thin panel or slender column deforms laterally under axial compression before reaching its material yield stress?

A. Galvanic corrosion

B. Creep rupture

C. Fatigue cracking

D. Buckling

D. Buckling

24. The moment of a force of 25N about a point is 2.5Nm. Find the perpendicular distance of force from that point.

A. 20cm

B. 10cm

C. 40cm

D. 30cm

B. 10cm

25. The landing gear of an aircraft is designed to provide:

A. Stability during flight

B. Shock absorption during landing

C. Steering capability on the ground

D. Aerodynamic lift

B. Shock absorption during landing

26. What are the different types of trusses?

A. Warren trusses

B. Fink trusses

C. Pratt trusses

D. All of the above

D. All of the above

27. This is the maximum weight exclusive of usable fuel.

A. maximum landing weight

B. maximum takeoff weight

C. maximum zero fuel weight

D. maximum ramp weight

C. maximum zero fuel weight

28. How does CG travel affect aircraft stability?

A. It affects lateral stability.

B. It has no effect on stability.

C. It affects directional stability.

D. It affects the longitudinal stability.

D. It affects the longitudinal stability.

29. A particle is moving in a circle with a radius of 10 meters. If its angular velocity is 2 rad/s, what are the radial and transverse components of its velocity?

A. Radial = 10 m/s, Transverse = 0 m/s

B. Radial = 20 m/s, Transverse = 10 m/s

C. Radial = 0 m/s, Transverse = 10 m/s

D. Radial = 10 m/s, Transverse = 20 m/s

A. Radial = 10 m/s, Transverse = 0 m/s

30. The first derivative of position with respect to time is ?

A. Acceleration

B. Position

C. None of the above

D. Velocity

D. Velocity

31. A slight increase in stress above the elastic limit will result in a breakdown of the material and cause it to deform permanently.

A. Necking

B. Yielding

C. Plastic Behavior

D. Elastic Region

B. Yielding

32. The CG envelope affects the _____ stability of an aircraft.

A. directional

B. longitudinal

C. lateral

D. vertical

C. lateral

33. The following are secondary control surfaces, except:

A. vortex generator

B. spoilers

C. slats

D. air brake

A. vortex generator

34. Which of the following statements is correct?

A. Maximum range for a propeller driven airplane occurs when the airplane is flying at a velocity such that Cl^3/2/Cd is maximum

B. Maximum endurance for a propeller driven airplane occurs when the airplane is flying at maximum power required

C. None statement provided is correct

D. Maximum range for a propeller driven airplane occurs when the airplane is flying at a velocity such that Cl/Cd is maximum

D. Maximum range for a propeller driven airplane occurs when the airplane is flying at a velocity such that Cl/Cd is maximum

35. The aircraft would maintain its new attitude after any disturbance to its equilibrium

A. Neutral Static Stability

B. Positive Dynamic Stability

C. Negative Static Stability

D. Positive Static Stability

A. Neutral Static Stability

36. A 2014-T6 aluminum alloy hollow circular tube has an outer diameter of 150 mm and inner diameter of 100 mm. If it is pinned at both ends, determine the largest axial load that can be applied to the tube without causing it to buckle.The tube is 6 m long. Use Young's modulus of 73.1 (10^9) Pa.

A. 415 kN

B. 405 kN

C. 410 kN

D. 400 kN

D. 400 kN

37. Which of the following is a condition for equilibrium of a rigid body?

A. The sum of the forces acting on the body must be zero.

B. The body must be in motion.

C. The body must be at rest.

D. The sum of the moments of the forces acting on the body must be zero.

D. The sum of the moments of the forces acting on the body must be zero.

38. What is the unit of strain?

A. No Unit

B. Pascal

C. Newton

D. Kilogram

A. No Unit

39. Which of the following statements about positive and negative stagger in biplane aircraft is true?

A. Positive stagger improves stability while negative stagger increases maneuverability.

B. Positive stagger increases maneuverability while negative stagger improves stability.

C. Positive stagger and negative stagger have the same effect on stability and maneuverability.

D. Biplane aircraft do not typically use positive or negative stagger in their wing designs.

A. Positive stagger improves stability while negative stagger increases maneuverability.

40. Due to the complexity of the structure of the fuselage and the arrangement of interior, it is customary to build a:

A. Full scale mock-up

B. Trial Aircraft

C. Full scale prototype

D. Dummy

A. Full scale mock-up

41. How are trusses and frames constructed?

A. By engineers using a variety of methods, including static analysis, dynamic analysis, and finite element analysis.

B. Both A and B

C. None of the above

D. By carpenters and other skilled laborers using a variety of methods, including welding, riveting, and bolting.

D. By carpenters and other skilled laborers using a variety of methods, including welding, riveting, and bolting.

42. A ball is thrown straight up into the air with an initial velocity of 20 m/s. What is its velocity after 3 seconds?

A. 5 m/s

B. 10 m/s

C. 20 m/s

D. 15 m/s

D. 15 m/s

43. Which of the following is a scalar quantity?

A. Mass

B. Acceleration

C. Velocity

D. Force

A. Mass

44. Which empennage configuration avoids blanketing of the rudders due to wing and forward fuselage at high angles of attack?

A. BOOM-MOUNTED TAIL

B. RING-TAIL

C. TWIN TAILS

D. Y-TAIL

C. TWIN TAILS

45. What factor predominantly determines the all-up-mass of Long-endurance, Long-range Role Aircraft?

A. Communications equipment

B. Engine power

C. Mass of the payload

D. Mass of the fuel

D. Mass of the fuel

46. A beam is supported by a hinge at one end and a roller at the other end. A load of 100 N is applied to the beam 2 meters from the hinge. What are the reactions at the hinge and the roller?

A. Hinge = 200 N, Roller = 0 N

B. Hinge = 150 N, Roller = 0 N

C. Hinge = 250 N, Roller = 0 N

D. Hinge = 100 N, Roller = 0 N

A. Hinge = 200 N, Roller = 0 N

47. A 5 kg block is pulled across a rough surface by a horizontal force of 20 N with a frictional force of 10 N opposing the motion. What is the acceleration of the block?

A. 3 m/s^2.

B. 5 m/s^2.

C. 2 m/s^2.

D. 4 m/s^2.

C. 2 m/s^2.

48. A car is moving at a constant speed of 60 km/h. What is the tangential component of its velocity?

A. 40 m/s

B. 10 m/s

C. 30 m/s

D. 20 m/s

D. 20 m/s

49. How does the centroid of a three-dimensional object differ from that of a two-dimensional figure?

A. The centroid of a three-dimensional object is a point, while that of a two-dimensional figure is a line

B. The centroid of a three-dimensional object is a point, while that of a two-dimensional figure is a plane

C. The centroid of a three-dimensional object is a line, while that of a two-dimensional figure is a point

D. The centroid of a three-dimensional object is a plane, while that of a two-dimensional figure is a point

A. The centroid of a three-dimensional object is a point, while that of a two-dimensional figure is a line

50. For a commercial passenger airliner designed with a cabin differential pressure of 8.5 psi, which fuselage cross-sectional shape minimizes bending stresses in the frames and skin under internal pressure?

A. Elliptical

B. Circular

C. Trapeziodal

D. Rectangular

B. Circular