1.
Atmospheric pressure at sea level is
Correct Answer
A. 14.7
Explanation
Atmospheric pressure at sea level is 14.7. This is the standard atmospheric pressure at sea level, also known as 1 atmosphere (atm). It is the pressure exerted by the weight of the atmosphere above a given point. This value is commonly used as a reference point for measuring pressure in various applications, such as weather forecasting and scuba diving.
2.
A barometer is designed to measure pressure in
Correct Answer
B. Inches of mercury
Explanation
A barometer is designed to measure pressure, and the unit commonly used for this measurement is inches of mercury. This unit refers to the height of a column of mercury that is supported by the atmospheric pressure. As the atmospheric pressure changes, the height of the mercury column will also change, allowing for the measurement of pressure. Pounds per square inch, milibars of alcohol, and ounces of air are not commonly used units for measuring pressure with a barometer.
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 acts vertically downward. In order for an airfoil to generate lift and overcome the force of weight, it must create a pressure difference between the upper and lower surfaces of the wing. This pressure difference creates an upward force, known as lift, which counteracts the weight of the aircraft. Drag and thrust are also important forces in aviation, but they are not the primary force that an airfoil has to defeat.
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 airborne. It is generated by the shape of the object's wings or airfoils, as air flows over them. This upward force is essential for the object to maintain altitude and control its flight.
5.
The force that acts parallel to the relative wind is
Correct Answer
B. Drag
Explanation
Drag is the force that acts parallel to the relative wind. When an object moves through a fluid (such as air or water), drag is the resistance force that opposes the motion of the object. It is caused by the interaction between the object and the fluid molecules. In the context of aerodynamics, drag is an important factor that affects the performance and efficiency of an aircraft. It is necessary to minimize drag in order to increase speed and reduce fuel consumption.
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 is the correct answer because it refers to the stress that resists the force that tends to cause one layer of material to slide over an adjacent layer. Shear stress occurs when two layers of material are parallel to each other and are subjected to forces in opposite directions. This causes the layers to slide past each other, and shear stress resists this sliding motion. Bending, tension, and torsion are different types of stresses that occur in different situations and are not directly related to the resistance of sliding layers.
7.
What is the design that uses any combination of logerons, stringers, bulkheads and frames in the construction of a fuselage called?
Correct Answer
D. Semi-monocoque
Explanation
A semi-monocoque design is a type of construction method for a fuselage that utilizes a combination of logerons, stringers, bulkheads, and frames. In this design, the load is distributed between the outer skin (monocoque) and the internal structural components (logerons, stringers, bulkheads, and frames), resulting in a lighter and stronger fuselage. This design is commonly used in modern aircraft as it provides a good balance between strength and weight efficiency.
8.
The structural member 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 run longitudinally along the fuselage or wings and help to distribute the load evenly throughout the structure. Stringers are typically made of lightweight materials such as aluminum or composite materials to minimize weight while maintaining structural integrity.
9.
The most common type of material used for fuselage construction is
Correct Answer
D. Aluminum alloy
Explanation
Aluminum alloy is the most common type of material used for fuselage construction. This is because aluminum alloys are lightweight, strong, and have good corrosion resistance. These properties make them ideal for aircraft structures, as they help to reduce the overall weight of the aircraft while maintaining structural integrity. Additionally, aluminum alloys can be easily formed into complex shapes, allowing for efficient manufacturing processes.
10.
The wing design used in most modern military aircraft is
Correct Answer
A. Cantilever
Explanation
The correct answer is cantilever. Cantilever wing design refers to a wing structure that is self-supporting and does not require external bracing or struts. It is a common design used in modern military aircraft as it provides better aerodynamic efficiency and reduces drag. The cantilever design allows for a sleeker and more streamlined aircraft, improving its performance and maneuverability.
11.
The fixed verticle 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 responsible for providing stability and directional control to the aircraft. It helps in preventing yawing motion and keeps the aircraft flying straight. The fin works in conjunction with the rudder, which is a movable control surface attached to the fin. The rudder is used to control the yawing motion of the aircraft, while the fin provides the necessary stability.
12.
Engine mounts are typically made of corrosion- resistant steel is able to withstand forces of
Correct Answer
C. 180000 to 200000 psi
Explanation
Engine mounts are typically made of corrosion-resistant steel because it is able to withstand high forces. The given answer range of 180000 to 200000 psi indicates the pressure per square inch that the steel can handle. This range suggests that the engine mounts are designed to endure significant stress and maintain their structural integrity under heavy loads and vibrations. This ensures the stability and safety of the engine within the vehicle.
13.
The main difference between inspection panels and plates is
Correct Answer
A. Size
Explanation
The main difference between inspection panels and plates is their size. Inspection panels are typically smaller in size and are used to provide access for inspection and maintenance purposes. On the other hand, plates are larger in size and are used to cover larger areas or openings.
14.
A network of ultrafine cracks that form on or under the surface of transparent plastic is called
Correct Answer
A. Crazing
Explanation
Crazing refers to the formation of a network of ultrafine cracks on or under the surface of transparent plastic. This phenomenon is often caused by stress or aging of the material, leading to a weakened appearance and potential loss of transparency. Crazing can occur in various plastic materials and is commonly observed in items such as eyeglass lenses or acrylic displays.
15.
What are the reference locations in the verticle 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 lines on the aircraft's fuselage that indicate the height of the aircraft above the water when it is in a level flight position. These reference points are important for various calculations and measurements related to the aircraft's stability and performance.
16.
Movement about the verticle axis is called
Correct Answer
B. Yaw
Explanation
Yaw refers to the movement about the vertical axis. It is the rotation of an object or vehicle in a horizontal plane, causing it to turn left or right. In aviation, yaw is controlled by the rudder, which helps to change the direction of the aircraft. Yaw is different from roll, which is the rotation about the longitudinal axis, pitch, which is the rotation about the lateral axis, and crab, which refers to the sideways movement of an aircraft due to crosswinds.
17.
Which flight control surface is a longitudinal control surface?
Correct Answer
C. Elevator
Explanation
The elevator is a longitudinal control surface that is responsible for controlling the pitch of an aircraft. It is located on the horizontal stabilizer at the rear of the aircraft and can be moved up or down. When the elevator is raised, the nose of the aircraft pitches up, and when it is lowered, the nose pitches down. This control surface is crucial for maintaining the aircraft's stability and controlling its altitude during flight.
18.
Which 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 responsible for controlling the pitch of an aircraft, allowing it to climb or descend. By deflecting the elevator, the pilot can adjust the angle of attack of the aircraft, which in turn affects its lift and therefore its altitude. The elevator works in conjunction with the horizontal stabilizer to provide stability and control during flight.
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 that the right aileron trailing edge is up and 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, allowing the aircraft to roll and turn to the right. By raising the trailing edge of the right aileron and lowering the trailing edge of the left aileron, the pilot can effectively control the bank angle 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 movable surfaces on the trailing edge of an aircraft's wings. They are used to increase lift and drag during certain phases of flight. By extending the flaps, the curvature of the wing increases, generating more lift. This is particularly useful during takeoff and landing when the aircraft needs more lift at lower speeds. However, the increased curvature also creates more drag, which helps to slow down the aircraft. Therefore, the purpose of wing flaps is to increase both lift and drag.
21.
The purpose of aircraft trim system is to
Correct Answer
C. Correct minor deviation in flight alttitude
Explanation
The purpose of an aircraft trim system is to correct minor deviations in flight altitude. This system helps maintain the desired level flight by adjusting the position of the control surfaces, such as elevators or stabilizers, to balance the aircraft's pitch. By making these adjustments, the trim system ensures that the aircraft maintains a steady altitude without the need for constant manual control input from the pilot.
22.
Matter is any substance that has mass and
Correct Answer
B. Occupies space
Explanation
The given statement defines matter as a substance that has mass and occupies space. This means that matter takes up physical space and has a definite volume. It implies that matter cannot exist in a void or occupy the same space as another matter simultaneously. The statement does not mention anything about matter being visible or having a constant volume or being unable to be compressed. Therefore, the correct answer is "occupies space" because it accurately represents the definition of matter provided in the statement.
23.
Atoms are made up of
Correct Answer
D. Protons, neutrons, electrons
Explanation
Atoms are made up of protons, neutrons, and electrons. Protons are positively charged particles found in the nucleus of an atom, while neutrons are neutral particles also located in the nucleus. Electrons are negatively charged particles that orbit the nucleus. These three components together form the structure of an atom. Molecules, on the other hand, are formed when atoms bond together through chemical interactions. Therefore, the correct answer is protons, neutrons, electrons.
24.
Electrons can be released from their outer orbit by the following forces except
Correct Answer
B. Cold
Explanation
Electrons can be released from their outer orbit by heat, chemical action, and changing magnetic fields. However, cold does not have enough energy to overcome the attractive forces holding electrons in their orbit. Therefore, cold 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
The electrical pressure that causes electrons to flow through a conductor is called electromotive force. This force is responsible for pushing the electrons and creating a flow of current in the circuit. It is often represented by the symbol EMF and is measured in volts. The other options mentioned in the question, such as chemical swap, crossfeed field, and transferring magnetic field, are not accurate terms for describing this phenomenon.
26.
If you apply 24 volts through a total resistance of 6 ohms in a series circuit, the amperage would be
Correct Answer
B. 4
Explanation
In a series circuit, the total resistance is the sum of individual resistances. In this case, the total resistance is 6 ohms. According to Ohm's Law (V = I * R), the current (amperage) can be calculated by dividing the voltage (24 volts) by the total resistance. Therefore, the amperage would be 4 amperes.
27.
A permanent magnet is produced from a material with
Correct Answer
B. High reluctance and low permeability
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 its magnetism over time. High reluctance means that the material resists the magnetic field, preventing it from easily passing through. Low permeability means that the material does not easily allow magnetic flux to pass through it. This combination of properties ensures that the magnet retains its magnetism for 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 material that can easily be magnetized and demagnetized, making it useful in applications such as electromagnets. When it is brought close to a permanent magnet, the magnetic field of the permanent magnet induces a magnetic field in the soft iron, causing it to become magnetized. This magnetization allows the soft iron to attract or repel other magnetic materials and interact with magnetic fields.
29.
The greater the current flow through an electromagnet, the
Correct Answer
B. Greater the strength
Explanation
The greater the current flow through an electromagnet, the greater the strength. This is because the strength of an electromagnet is directly proportional to the amount of current flowing through it. As the current increases, more magnetic field lines are generated, resulting in a stronger magnetic force. Therefore, the greater the current flow, the greater the strength of the electromagnet.
30.
Current flow in most aircraft circuits is controlled by
Correct Answer
D. Switches
Explanation
In most aircraft circuits, the current flow is controlled by switches. Switches are used to open or close the circuit, allowing or preventing the flow of electric current. They are used to control various systems and components in an aircraft, such as lights, avionics, engines, and more. Fuses are used to protect the circuit from overcurrent, but they do not control the flow of current. Signals are used for communication and do not directly control the current flow. Batteries provide the source of electrical power but do not control the flow of current in the circuit.
31.
The majority of aircraft circuit protection devices are normally located
Correct Answer
A. In the aircraft cabin
Explanation
Aircraft circuit protection devices are typically located in the aircraft cabin to ensure easy access and maintenance. Placing them in the cabin allows for quick identification and troubleshooting of any issues that may arise. Additionally, it ensures that these devices are protected from environmental factors such as extreme temperatures or moisture that could potentially affect their functionality.
32.
What term descibes current that reverses its direction at regularly intervals?
Correct Answer
D. Alternating
Explanation
The term that describes current that reverses its direction at regular intervals is "alternating". This type of current is commonly used in household electricity, where the flow of electrons constantly changes direction. Unlike direct current, which flows in only one direction, alternating current is characterized by its periodic reversal of polarity. This allows for efficient transmission of electricity over long distances and enables the operation of various electrical devices.
33.
The methods used to cool AC generators are
Correct Answer
B. Engine oil and blast air
Explanation
The correct answer is engine oil and blast air. AC generators require cooling to prevent overheating. Engine oil is used to lubricate the moving parts of the generator and also acts as a coolant by absorbing and dissipating heat. Blast air is used to provide additional cooling by blowing air over the generator, helping to remove heat from the system. This combination of engine oil and blast air effectively cools the AC generator and ensures its proper functioning.
34.
The output of the csd used to drive a 60/80 kilovolt ampere generator is approximately
Correct Answer
C. 8,000 rpm
Explanation
The correct answer is 8,000 rpm. The output of the csd (constant speed drive) used to drive a 60/80 kilovolt ampere generator is approximately 8,000 rpm.
35.
The USS on the 60/80 KVA generator CSD actuatesat
Correct Answer
C. 365 Hz
Explanation
The USS on the 60/80 KVA generator CSD actuates at 365 Hz.
36.
What supplies rotary power to the input gear of the CSD
Correct Answer
A. Accessory gearbox
Explanation
The accessory gearbox is responsible for supplying rotary power to the input gear of the CSD. It is a component that is connected to the engine and provides power to various accessories such as the alternator, air conditioning compressor, and hydraulic pumps. This gearbox transfers power from the engine to the input gear of the CSD, allowing it to function properly.
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. A battery's internal component that supports the active chemical materials is called a plate. The plate acts as a framework or grid that holds the active materials, allowing for the chemical reactions that generate electricity to occur.
38.
A 24-volt nickel-cadmium battery has
Correct Answer
B. 19 cells
Explanation
A 24-volt nickel-cadmium battery typically consists of 12 cells, each producing approximately 2 volts. However, in this case, the battery has 19 cells, which means each cell is producing slightly less than 2 volts. The total voltage of the battery is still 24 volts, but it is achieved by having more cells with slightly lower voltage output.
39.
The nickel-cadmium battery can be fully charged only by
Correct Answer
B. Constant current
Explanation
Constant current is the correct answer because nickel-cadmium batteries have a specific charging profile that requires a constant current to reach full charge. This means that the charging current remains constant throughout the charging process until the battery is fully charged. Using pulsating, varying, or eddy currents would not provide the necessary consistent flow of electricity required for optimal charging and could potentially damage the battery.
40.
What type of motor can operate on alternating current (AC) or direct current (DC)?
Correct Answer
C. Universal
Explanation
A universal motor can operate on both alternating current (AC) and direct current (DC). This type of motor is designed with a special winding configuration that allows it to work with both types of currents. The universal motor is commonly used in appliances and power tools because of its versatility. It can be connected to AC power when available, but can also function on DC power sources such as batteries. This makes it a suitable choice for applications where the power source may vary.
41.
A shunt type motor has
Correct Answer
C. Low starting torque and good speed regulation
Explanation
A shunt type motor has low starting torque and good speed regulation. This means that it does not have a strong initial force to start rotating, but once it starts, it can maintain a consistent speed even under varying loads. This is because the field winding is in parallel (shunt) with the armature, allowing the motor to regulate its speed effectively.
42.
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.
43.
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 force causes a solid to change permanently, it means that the solid has passed its elastic limit. The elastic limit is the maximum stress 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 "passed the elastic limit."
44.
The most outstanding characteristic of a liquid is its
Correct Answer
D. Ability to conform to the shape of its container
Explanation
A liquid's ability to conform to the shape of its container refers to its property of taking the shape of the container it is placed in. Unlike solids, which have a fixed shape, liquids can flow and change their shape to fit the container. This characteristic allows liquids to fill the container evenly, regardless of its shape or size. It is this property that distinguishes liquids from other states of matter and makes them useful in various applications such as filling bottles, pouring liquids, and mixing substances.
45.
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 a piston pushing the fluid. A pneudraulic system combines both pneumatic and hydraulic principles, using compressed air to generate mechanical force. The piston, driven by the compressed air, pushes the fluid through the system, creating flow. This flow is essential for the proper functioning of the system, allowing it to perform various tasks such as actuating cylinders or controlling valves.
46.
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. He is known for 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 in the 17th century and published his findings in "The Sceptical Chymist" in 1661. His work laid the foundation for the understanding of gas behavior and the development of the field of gas laws.
47.
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
When 50 pounds per square inch (psi) of cylinder pressure acts on a 5-square-inch piston head, the resulting force can be calculated by multiplying the pressure by the area. Therefore, the resulting force is 50 psi * 5 square inches = 250 pounds.
48.
When an 8-square-inch piston moves 5 inches within a cylinder, what volume of liquid is
displaced?
Correct Answer
B. 40 cubic inches
Explanation
When an 8-square-inch piston moves 5 inches within a cylinder, 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). Therefore, the volume of liquid displaced is 40 cubic inches.
49.
Turbulence affects fluid-flow in a hydraulic line by
Correct Answer
C. Creating resistance and loss of energy
Explanation
Turbulence in a hydraulic line creates resistance and loss of energy. When fluid flows through a hydraulic line, turbulence occurs when there is a disruption in the smooth flow of the fluid. This disruption causes the fluid to move in an irregular and chaotic manner, resulting in increased resistance to flow. As a result, energy is lost in overcoming this resistance, leading to a decrease in the overall efficiency of the hydraulic system.
50.
A tube whose cross-section area is gradually reduced to a smaller size diameter is called a
Correct Answer
D. Venturi.
Explanation
A tube whose cross-section area is gradually reduced to a smaller size diameter is called a venturi. This type of tube is commonly used in fluid mechanics to create a pressure difference, which allows for the measurement of flow rate or the mixing of fluids. The gradual reduction in diameter causes the fluid velocity to increase, resulting in a decrease in pressure according to Bernoulli's principle. The venturi effect is utilized in various applications, such as in carburetors, air conditioning systems, and medical devices.