1.
Atmospheric pressure at sea level is
Correct Answer
A. 14.7 pounds per square inch (psi)
Explanation
Atmospheric pressure at sea level is commonly measured as 14.7 pounds per square inch (psi). This value represents the average pressure exerted by the Earth's atmosphere at sea level. It is important to note that atmospheric pressure can vary slightly depending on factors such as weather conditions and altitude. However, 14.7 psi is considered the standard value used for reference in various scientific and engineering applications.
2.
A barometer is designed to measure pressure in
Correct Answer
B. Inches of mercury
Explanation
A barometer is a device used to measure atmospheric pressure. The most common unit for measuring pressure using a barometer is inches of mercury (inHg). This unit is derived from the height of a column of mercury that is supported by the atmospheric pressure. As the pressure changes, the height of the mercury column also changes, allowing for the measurement of pressure in inches of mercury. This unit is widely used in meteorology and aviation.
3.
The primary force an airfoil has to defeat is
Correct Answer
D. Weight
Explanation
The primary force an airfoil has to defeat is weight. Weight is the force exerted by gravity on an object, and it acts in the downward direction. In order for an airfoil, such as an airplane wing, to generate lift and stay airborne, it must overcome the force of weight. By generating enough lift through the shape and angle of the airfoil, the upward force can counteract the downward force of weight, allowing the aircraft to stay aloft.
4.
The force that acts upward at a right angle to the direction of the relative wind is
Correct Answer
A. Lift.
Explanation
The force that acts upward at a right angle to the direction of the relative wind is called lift. Lift is the force that allows an object, such as an airplane, to overcome gravity and stay in the air. It is generated by the shape of the object's wings or airfoils and the flow of air over them. This upward force counters the weight of the object, allowing it to stay aloft.
5.
The force that acts parallel to the relative wind is
Correct Answer
B. Drag.
Explanation
The force that acts parallel to the relative wind is drag. Drag is the resistance force that opposes the motion of an object through a fluid, such as air. In the context of aerodynamics, when an object, such as an airplane, moves through the air, drag is generated due to the friction between the object and the air molecules. This force acts in the direction opposite to the motion of the object and is parallel to the relative wind, which is the direction of the airflow relative to the object. Therefore, drag is the correct answer.
6.
The stress that resists the force tending to cause one layer of material to slide over an adjacent layer is called
Correct Answer
D. Shear.
Explanation
Shear stress refers to the stress that resists the force that tries to cause one layer of material to slide over an adjacent layer. It occurs parallel to the plane of contact between the layers and acts in opposite directions on each layer. Bending stress is related to the deformation of a material due to bending, tension stress is caused by the pulling force applied to a material, and torsion stress is the stress caused by twisting or rotating forces. However, shear stress specifically addresses the resistance to sliding between layers, making it the correct answer in this case.
7.
What is the design that uses any combination of longerons, stringers, bulkheads, and frames in the construction of the fuselage called?
Correct Answer
D. Semi-monocoque.
Explanation
A semi-monocoque design is a type of fuselage construction that combines longerons, stringers, bulkheads, and frames. In this design, the skin of the fuselage carries a significant portion of the structural load, while the internal framework provides additional support and strength. This design is commonly used in modern aircraft as it offers a good balance between strength and weight.
8.
The structural members used to give shape to the aircraft and provide a means for attaching the skin to the structure are called
Correct Answer
C. Stringers.
Explanation
Stringers are structural members that are used to give shape to the aircraft and provide a means for attaching the skin to the structure. They are long, thin strips of material that run longitudinally along the fuselage or wing. Stringers help to distribute the loads and stresses evenly throughout the structure, providing strength and rigidity. They also help to maintain the shape of the aircraft and prevent deformation. Therefore, stringers are the correct answer in this case.
9.
The most common type of material used for fuselage construction is
Correct Answer
D. Aluminum alloy.
Explanation
The most common type of material used for fuselage construction is aluminum alloy. This is because aluminum alloys offer a good balance of strength and weight, making them ideal for aircraft structures. They have high strength-to-weight ratio, corrosion resistance, and can withstand the stresses and pressures experienced during flight. Additionally, aluminum alloys are relatively easy to work with and can be formed into complex shapes, making them suitable for the curved and streamlined design of fuselages. Steel, titanium, and magnesium are also used in aircraft construction, but aluminum alloy is the most commonly used material for fuselages.
10.
The wing design used on most modern military aircraft is
Correct Answer
A. Cantilever.
Explanation
The wing design used on most modern military aircraft is cantilever. A cantilever wing design refers to a wing that is self-supporting and does not require external bracing or additional support structures. This design allows for a sleek and streamlined appearance, reducing drag and improving aerodynamic performance. Cantilever wings are commonly used in modern military aircraft to enhance maneuverability, speed, and overall performance in combat situations.
11.
The fixed vertical surface of the empennage is called the
Correct Answer
D. Fin.
Explanation
The fixed vertical surface of the empennage is called the fin. The fin is a vertical stabilizer that provides stability and control to the aircraft during flight. It helps to maintain the aircraft's yaw stability by resisting any side-to-side movement. The fin is typically located at the rear of the aircraft and is an essential component of the empennage, along with the horizontal stabilizer and elevator.
12.
Engine mounts are typically made of corrosion-resistant steel that is able to withstand forces of
Correct Answer
C. 180,000 to 200,000 psi.
Explanation
Engine mounts are typically made of corrosion-resistant steel that is able to withstand forces of 180,000 to 200,000 pounds per square inch (psi). This range of psi ensures that the engine mounts can endure the high levels of stress and pressure generated by the engine during operation.
13.
The main difference between inspection plates and panels is
Correct Answer
A. Size.
Explanation
The main difference between inspection plates and panels is their size. Inspection plates are typically smaller in size and are used for accessing specific areas or components for inspection or maintenance purposes. On the other hand, panels are larger and are used to cover larger areas or enclosures. The size difference allows for easier access and maintenance of different parts or systems in a given structure or equipment.
14.
A network of ultra cracks that form on or under the surfave of transparent pastics is called
Correct Answer
A. Crazing.
Explanation
Crazing refers to the formation of a network of fine cracks on or under the surface of transparent plastics. This phenomenon typically occurs due to the stress or strain applied to the material, causing it to develop small fractures that resemble a spider web pattern. Casting, fretting, and pitting are unrelated terms and do not describe the specific cracking behavior observed in crazing.
15.
What are the reference locations in the vertical direction measured from a reference datum that is usually well below the aircraft called?
Correct Answer
B. Waterlines.
Explanation
The reference locations in the vertical direction measured from a reference datum that is usually well below the aircraft are called waterlines. Waterlines are horizontal reference lines that are used to determine the position of various components of an aircraft, such as the wings, fuselage, and tail, in relation to the waterline. These reference locations help in ensuring proper balance and stability of the aircraft during flight and are crucial for design, maintenance, and performance purposes.
16.
Movement about the vertical axis is called
Correct Answer
B. Yaw.
Explanation
Movement about the vertical axis is called "yaw." Yaw refers to the rotation of an object or body around its vertical axis, which is an imaginary line passing through the center of gravity and extending vertically from the object. This movement causes the object to turn left or right, similar to the motion of a ship or an airplane changing its direction horizontally. Roll refers to the rotation around the longitudinal axis, pitch refers to the rotation around the lateral axis, and crab refers to a sideways movement caused by crosswinds.
17.
Which flight control surface is a longitudinal control surface
Correct Answer
B. Aileron.
Explanation
The correct answer is Aileron. The aileron is a flight control surface that is located on the trailing edge of the wing and is used to control the roll of an aircraft. It is responsible for creating differential lift on the wings, which allows the aircraft to bank and turn. The rudder is a vertical control surface used for yaw control, the elevator is a horizontal control surface used for pitch control, and the wing flaps are used to increase lift and drag during takeoff and landing. Therefore, the aileron is the correct answer as it is specifically designed for longitudinal control.
18.
Wich of these is attached to the trailing edge of a horizontal stabilizer?
Correct Answer
D. Elevator.
Explanation
The elevator is attached to the trailing edge of a horizontal stabilizer. It is a movable control surface that is used to control the pitch of an aircraft. By changing the angle of the elevator, the pilot can control the aircraft's nose-up or nose-down attitude, allowing for changes in altitude. Flaps are attached to the wings and are used to increase lift during takeoff and landing. Spoilers are also attached to the wings and are used to decrease lift and increase drag. The rudder is attached to the vertical stabilizer and is used to control the yaw of the aircraft.
19.
When making a right turn, the relative position of the ailerons is the right aileron trailing edge is
Correct Answer
B. Up, left aileron trailing edge is down.
Explanation
When making a right turn, the relative position of the ailerons is such that the right aileron trailing edge is up, while the left aileron trailing edge is down. This configuration helps to increase the lift on the right wing and decrease the lift on the left wing, which helps to bank the aircraft to the right and initiate the turn. By raising the trailing edge of the right aileron and lowering the trailing edge of the left aileron, the pilot can effectively control the roll of the aircraft and maintain stability during the turn.
20.
The purpose of wing flaps is to
Correct Answer
A. Increase lift and drag.
Explanation
Wing flaps are used to increase lift and drag. When the flaps are extended, they increase the surface area of the wing, which in turn generates more lift. This is particularly useful during takeoff and landing when the aircraft needs more lift to maintain a safe speed and altitude. Additionally, the increased drag caused by the extended flaps helps to slow down the aircraft, making it easier to control during landing. Therefore, the purpose of wing flaps is to increase both lift and drag.
21.
The purpose of aircraft trim systems is to
Correct Answer
C. Correct minor deviations in flight attitude.
Explanation
Aircraft trim systems are designed to adjust the aircraft's control surfaces in order to maintain a desired flight attitude. These systems help to correct any minor deviations in the aircraft's pitch, roll, or yaw, ensuring that the aircraft stays in a stable and controlled state of flight. By making these adjustments, the trim systems help pilots to maintain a balanced and efficient flight, without the need for constant manual control inputs.
22.
Matter is any substance that has mass and
Correct Answer
B. Occupies space.
Explanation
The correct answer is "occupies space" because matter refers to anything that takes up space and has mass. This means that matter has a physical presence and can be measured in terms of volume. Therefore, the statement "occupies space" accurately describes one of the fundamental characteristics of matter.
23.
Atoms are made up of
Correct Answer
D. Protons, neutrons and electrons.
Explanation
Atoms are the basic building blocks of matter, and they are composed of three main subatomic particles: protons, neutrons, and electrons. Protons have a positive charge, neutrons have no charge, and electrons have a negative charge. These particles are held together in the nucleus of an atom, with protons and neutrons making up the nucleus and electrons orbiting around it. Therefore, the correct answer is that atoms are made up of protons, neutrons, and electrons.
24.
Electrons can be released from their outer orbit by all of the following forces except
Correct Answer
B. Cold.
Explanation
Electrons can be released from their outer orbit by various forces such as heat, chemical action, and changing magnetic fields. However, cold temperatures do not have enough energy to overcome the binding forces holding electrons in their orbits. Therefore, cold is the only force mentioned that cannot release electrons from their outer orbit.
25.
What is the electrical pressure that causes electrons to flow through the conductor called?
Correct Answer
C. Electromotive force.
Explanation
Electromotive force is the correct answer because it refers to the electrical pressure that causes electrons to flow through a conductor. It is the driving force that pushes the electrons in a circuit, enabling the flow of electrical current. The other options, such as chemical swap, crossfeed field, and transferring magnetic field, do not accurately describe the electrical pressure that causes electron flow.
26.
If you apply 24 volts through a total resistance of 6 ohms is a series circut, the amperage would be
Correct Answer
B. 4.
Explanation
When 24 volts are applied to a total resistance of 6 ohms in a series circuit, the amperage can be calculated using Ohm's Law, which states that current (amperage) is equal to voltage divided by resistance. In this case, the current can be calculated as 24 volts divided by 6 ohms, which equals 4 amperes.
27.
A permanent magnet is produced from a material with
Correct Answer
B. High reluctance and low permability.
Explanation
A permanent magnet is produced from a material with high reluctance and low permeability because these properties allow the material to resist the flow of magnetic flux and retain a strong magnetic field. High reluctance means that the material does not easily allow magnetic flux to pass through it, while low permeability means that the material does not easily become magnetized. This combination of properties is essential for creating a permanent magnet that can maintain its magnetic field over a long period of time.
28.
When soft iron is brought close to a permanent magnet it is
Correct Answer
D. Magnetized.
Explanation
When soft iron is brought close to a permanent magnet, it becomes magnetized. Soft iron is a ferromagnetic material, which means it can be easily magnetized and demagnetized. When it is brought close to a permanent magnet, the magnetic field of the permanent magnet induces a magnetic field in the soft iron, aligning its domains and making it temporarily magnetic. This magnetization disappears when the soft iron is no longer in the presence of the permanent magnet. Therefore, the correct answer is magnetized.
29.
The greater the current flow through an electromagnet, the
Correct Answer
B. Greater the strength.
Explanation
The strength of an electromagnet is directly proportional to the current flow through it. As the current increases, the magnetic field produced by the electromagnet becomes stronger. This is because the magnetic field is created by the alignment of the magnetic domains within the core material, and a higher current flow leads to a greater alignment of these domains, resulting in a stronger magnetic field. Therefore, the greater the current flow through an electromagnet, the greater its strength.
30.
Current flow in the most aircraft circuits is controlled by
Correct Answer
D. Switches.
Explanation
In aircraft circuits, the current flow is controlled by switches. Switches are used to open or close the circuit, allowing or stopping the flow of electric current. They act as control devices that enable the pilot or operator to activate or deactivate various electrical components or systems in the aircraft. Fuses protect the circuit from excessive current, batteries provide the power source, and signals are used for communication or indicating purposes. However, neither fuses, batteries, nor signals directly control the current flow in aircraft circuits.
31.
The majority of the aircraft circuit protection devices are normally located
Correct Answer
A. In the aircraft cabin.
Explanation
The correct answer is in the aircraft cabin. This is because the aircraft cabin is the central location where the majority of the aircraft's electrical systems and components are housed. Placing the circuit protection devices in the cabin allows for easy access and maintenance. Additionally, locating them in the cabin ensures that they are protected from external elements and potential damage.
32.
What term describes current that reverses its direction at regularly recurring intervals?
Correct Answer
D. Alternating
Explanation
The term that describes current that reverses its direction at regularly recurring intervals is "alternating." This type of current is commonly used in electrical power systems, where the flow of electricity changes direction periodically. Unlike direct current, which flows in only one direction, alternating current alternates between positive and negative directions, allowing for efficient transmission of electricity over long distances.
33.
The methods used to cool brushless alternating current (AC) generators are
Correct Answer
B. Engine oil and blast air.
Explanation
The correct answer is engine oil and blast air. Brushless AC generators require cooling methods to prevent overheating. Engine oil is used to cool the generator's internal components, such as the stator and rotor windings, by dissipating heat. Blast air is also used to cool the generator by blowing air over the external surfaces, helping to remove heat generated during operation. This combination of engine oil and blast air provides an effective cooling system for brushless AC generators.
34.
The output of the constant speed drive (CSD) used to drive a 60/80 kilovolt ampere (KVA) generator is approximately
Correct Answer
C. 8,000 RPM
Explanation
The correct answer is 8,000 RPM. The constant speed drive (CSD) is used to drive a 60/80 KVA generator, and the output of the CSD is approximately 8,000 RPM. This means that the generator is designed to operate at a speed of 8,000 revolutions per minute.
35.
The underspeed switch (USS) on the 60/80 kilovolt ampere (KVA) generator constant speed drive (CSD) actuates at
Correct Answer
C. 365 Hz.
Explanation
The underspeed switch (USS) on the 60/80 kilovolt ampere (KVA) generator constant speed drive (CSD) actuates at 365 Hz.
36.
What supplies rotary power to the input gear of the constant speed drive (CSD)?
Correct Answer
A. Accessory gearbox.
Explanation
The accessory gearbox supplies rotary power to the input gear of the constant speed drive (CSD). This means that the accessory gearbox is responsible for providing the necessary power to the CSD, allowing it to function properly. The other options, such as the transmission shaft, torque converter, and hydraulic gear, are not directly involved in supplying power to the CSD.
37.
A battery's internal component that is a grid or framework which supports the active chemical materials is called the
Correct Answer
A. Plate.
Explanation
The correct answer is plate. In a battery, the plate refers to the internal component that acts as a grid or framework to support the active chemical materials. The plate helps in the flow of electrons during the charging and discharging process of the battery. The active chemical materials are usually coated on the surface of the plate, allowing for the conversion of chemical energy into electrical energy.
38.
A 24-volt nickel-cadmium battery has
Correct Answer
B. 19 cells.
Explanation
The correct answer is 19 cells because a 24-volt nickel-cadmium battery typically consists of 1.2-volt cells. Therefore, dividing 24 volts by 1.2 volts per cell gives us a total of 20 cells. However, it is important to note that one of the cells is typically used as a voltage regulator, which brings the total number of usable cells to 19.
39.
The nickel-cadmium battery can be fully charged only by
Correct Answer
B. Constant current.
Explanation
The nickel-cadmium battery can be fully charged only by a constant current. This is because a constant current ensures a steady flow of electrons into the battery, allowing for a controlled and efficient charging process. Pulsating current, varying current, and eddy current would not provide a consistent and stable flow of electrons, which could result in incomplete or inefficient charging of the battery.
40.
A shunt-type motor has
Correct Answer
C. Low starting torque and good speed regulation.
Explanation
A shunt-type motor has a field winding in parallel with the armature, which allows it to have good speed regulation. This means that it can maintain a relatively constant speed even when there are changes in load. However, it has low starting torque, which means it may struggle to start heavy loads.
41.
The three states of matter are
Correct Answer
D. Liquids, gases, and solids.
Explanation
The three states of matter are liquids, gases, and solids. Liquids have a definite volume but not a definite shape, gases have neither a definite volume nor a definite shape, and solids have both a definite volume and a definite shape. Minerals and organic substances are not states of matter, but rather types of substances that can exist in different states of matter.
42.
When any force causes a solid to change permanently, the solid is said to have
Correct Answer
A. Passed the elastic limit.
Explanation
When a solid is subjected to a force that causes it to change permanently, it means that the solid has exceeded its elastic limit. The elastic limit is the maximum stress or force that a material can withstand without undergoing permanent deformation. Once the elastic limit is surpassed, the solid loses its ability to return to its original shape and size after the force is removed. Therefore, the correct answer is that the solid has passed the elastic limit.
43.
The most outstanding characteristic of a liquid is its
Correct Answer
D. Ability to conform to the shape of its container.
Explanation
The correct answer is the ability to conform to the shape of its container. Unlike solids, liquids do not have a fixed shape and can take the shape of the container they are placed in. This is due to the weak intermolecular forces between liquid particles, allowing them to flow and move freely. Liquids are not rigid, as they can be poured or transferred from one container to another. They also cannot be compressed within their container, as their particles are already close together.
44.
What usually produces flow in a pneudraulic system?
Correct Answer
B. Piston pushing the fluid.
Explanation
In a pneudraulic system, flow is typically produced by the piston pushing the fluid. The piston creates pressure within the system, which then forces the fluid to flow through the system. This flow is essential for the proper functioning of the pneudraulic system, as it allows for the transfer of power and the operation of various components. The relief valve, scrupper, and selector valve may play important roles in controlling the flow or regulating the pressure, but they do not directly produce the flow in the system.
45.
Who was among the first to study the compressibility of gases?
Correct Answer
B. Boyle.
Explanation
Boyle was among the first to study the compressibility of gases. His work in the 17th century led to Boyle's Law, which states that the volume of a gas is inversely proportional to its pressure, when temperature is held constant. Boyle conducted experiments using a J-shaped tube filled with mercury and observed the relationship between the volume and pressure of gases. His contributions laid the foundation for the understanding of gas behavior and the development of the field of thermodynamics.
46.
If 50 pounds per square inch (PSI) of cylinder pressure acts on a 5-square-inch piston head, what will the resulting force be?
Correct Answer
C. 250 pounds.
Explanation
The resulting force can be calculated by multiplying the cylinder pressure (50 PSI) by the piston head area (5 square inches). This gives us a force of 250 pounds.
47.
When a 8-square-inch piston moves 5 inches within a cylinder, what volume of liquid is displaced?
Correct Answer
B. 40 cubic inches.
Explanation
The volume of liquid displaced can be calculated by multiplying the area of the piston (8 square inches) by the distance it moves (5 inches). This gives us a volume of 40 cubic inches.
48.
Turbulance affects fluid-flow in a hydraulic line by
Correct Answer
C. Creating resistance and loss of energy.
Explanation
Turbulence in a hydraulic line disrupts the smooth flow of fluid, causing resistance and loss of energy. When turbulence occurs, the fluid flow becomes chaotic and irregular, leading to increased friction and resistance within the system. This resistance results in a loss of energy as the fluid encounters obstacles and experiences internal friction. Therefore, turbulence in a hydraulic line creates resistance and causes a decrease in energy efficiency.
49.
A ture whose cross-section area is gradually reduced to smaller size diameter is called a
Correct Answer
D. Venturi.
Explanation
A venturi is a tube with a gradually decreasing cross-sectional area, which results in an increase in fluid velocity. This phenomenon is known as the venturi effect. The reduction in diameter creates a pressure difference between the wider and narrower sections of the tube. This principle is utilized in various applications such as fluid flow measurement and creating suction in devices like vacuum cleaners. A torus is a doughnut-shaped object, a pipette is a laboratory tool used for transferring small amounts of liquid, and a vortex refers to the swirling motion of fluids.
50.
The purpose of a hydraulic reservoir are to
Correct Answer
D. Replenish fluid, allow for thermal expansion, and provide a means of bleeding air from the system.
Explanation
The purpose of a hydraulic reservoir is to replenish fluid, allow for thermal expansion, and provide a means of bleeding air from the system. Replenishing fluid is important to ensure that the hydraulic system always has an adequate amount of fluid to operate effectively. Allowing for thermal expansion is necessary because as the fluid heats up during operation, it expands and needs space to accommodate this expansion. Lastly, providing a means of bleeding air from the system is crucial as air in the hydraulic system can cause inefficiencies and potential damage.