高级技师英语试题答案

高级技师英语试题答案
Part I: Multiple Choice Questions (30 points)
1. The term "mechanical system" refers to:
A. A system that operates through electrical signals.
B. A system that uses mechanical components to transmit power and motion.
C. A system that relies on hydraulic pressure for functioning.
D. A system that is controlled by computer programs.
Answer: B
2. Which of the following is NOT a common type of welding?
A. Arc welding
B. Oxy-fuel welding
C. Laser welding
D. Thermal welding
Answer: D
3. The unit of pressure in the International System of Units (SI) is:
A. Pascal (Pa)
B. Newton (N)
C. Kilogram-force (kgf)
D. Pounds per square inch (psi)
Answer: A
4. The purpose of a hydraulic system is to:
A. Generate heat
B. Transmit motion and force
C. Control temperature
D. Filter liquids
Answer: B
5. The term "CAD" stands for:
A. Computer-Aided Design
B. Computer-Aided Drafting
C. Computer-Aided Development
D. Computer-Aided Diagnosis
Answer: B
6. Which of the following materials is NOT typically used in electrical wiring?
A. Copper
B. Aluminum
C. Iron
D. Plastic
Answer: C
7. The function of a bearing in a mechanical system is to:
A. Transmit power
B. Reduce friction
C. Store energy
D. Amplify signals
Answer: B
8. The process of converting alternating current (AC) to direct current (DC) is known as:
A. Rectification
B. Inversion
C. Oscillation
D. Modulation
Answer: A
9. In the context of mechanical engineering, "tolerance" refers to:
A. The maximum allowable temperature variation.
B. The degree of deviation from a specified dimension.
C. The time allowed for a machine to complete a cycle.
D. The amount of pressure a component can withstand. Answer: B
10. The primary function of a gearbox is to:
A. Increase rotational speed
B. Decrease rotational speed
C. Increase torque
D. Both A and C
Answer: D
Part II: Short Answer Questions (30 points)
11. Explain the difference between "hardness" and "toughness" in materials science.
- Hardness is a measure of a material's resistance to deformation or penetration, typically assessed through tests like the Rockwell or Brinell test. It indicates how difficult it is to scratch or indent the material.
- Toughness, on the other hand, refers to a material's
ability to absorb energy and plastically deform without fracturing or breaking. It is a measure of the material's resistance to fracture when subjected to stress.
12. Describe the role of a capacitor in an electrical circuit.
A capacitor is a component that stores electrical energy in
an electric field. Its primary role in a circuit is to
maintain a steady voltage, filter out noise, store charge,
and release it when needed. Capacitors are used in various applications, including power supply filtering, signal processing, and energy storage.
13. What is the purpose of a cam in a mechanical system?
A cam is a mechanical component used to convert rotational motion into linear motion, often to operate or control the motion of other mechanical parts. It is typically a rotating wheel or disc with a profiled surface that interacts with a follower, such as a lever or a push rod, to generate the desired motion.
14. Explain the concept of "thermal expansion" and its implications for mechanical design.
Thermal expansion is the phenomenon where materials expand when heated and contract when cooled. This can lead to
problems in mechanical design if not accounted for, as it can cause parts to bind, create clearances, or induce stress when materials expand or contract due to temperature changes. Designers must consider these effects to ensure proper functioning and longevity of the system.
15. Describe the function of a solenoid in an electrical system.
A solenoid is a coil of wire that, when an electric current passes through it, generates a magnetic field. This magnetic field can attract or repel ferromagnetic materials, such as iron. Solenoids are used in various applications, including switches, valves, and actuators, to control the flow of
fluids or the operation of mechanical devices.
Part III: Essay Questions (40 points)
16. Discuss the importance of precision measurement in mechanical engineering and provide examples of tools and techniques used for such measurements.
Precision measurement is crucial in mechanical engineering to ensure the accuracy and functionality of components and systems. It helps in maintaining tolerances, diagnosing problems, and verifying the quality of work. Common tools for precision measurement include calipers, micrometers, dial indicators, laser distance meters, and coordinate measuring machines (CMMs). Techniques involve direct and indirect measurements, statistical。