Mechanical Engineer Interview Questions with Answers
Mechanical engineering is one of the most versatile and in-demand engineering disciplines. Whether you’re preparing for an entry-level position or a senior role, mechanical engineer interviews typically assess your technical knowledge, problem-solving skills, and understanding of engineering principles. To help you get ready, here are 15 commonly asked mechanical engineering interview questions with concise and effective answers.
1. What is the difference between stress and strain?
Answer: Stress is the internal force per unit area within a material, while strain is the deformation or displacement it experiences due to that stress.
2. Define entropy.
Answer: Entropy is a measure of disorder or randomness in a system; it increases in any spontaneous process.
3. What is the second law of thermodynamics?
Answer: It states that heat cannot spontaneously flow from a colder body to a hotter body, and that entropy in an isolated system always increases.
4. What is the difference between a pump and a compressor?
Answer: A pump moves liquids, while a compressor is used to increase the pressure of gases.
5. Explain the principle of conservation of energy.
Answer: Energy cannot be created or destroyed; it can only be transformed from one form to another.
6. What is the purpose of a flywheel in an engine?
Answer: A flywheel stores rotational energy and helps maintain consistent engine speed by smoothing out fluctuations.
7. What is cavitation in pumps?
Answer: Cavitation occurs when vapor bubbles form in a liquid due to local low pressure, potentially damaging the pump.
8. What is the difference between laminar and turbulent flow?
Answer: Laminar flow is smooth and orderly, while turbulent flow is chaotic with eddies and vortices.
9. What are the main types of heat transfer?
Answer: Conduction, convection, and radiation.
10. What is a four-stroke engine?
Answer: An internal combustion engine that completes a power cycle in four strokes: intake, compression, power, and exhaust.
11. Define modulus of elasticity.
Answer: It is the ratio of stress to strain within the elastic limit of a material, also called Young’s modulus.
12. What is the function of a bearing?
Answer: A bearing reduces friction and supports rotating or moving parts.
13. Explain the concept of thermal expansion.
Answer: Materials expand in volume when their temperature increases due to increased molecular motion.
14. What is meant by ‘factor of safety’?
Answer: It’s the ratio of the maximum load a component can withstand to the intended load, providing a safety margin.
15. What is the use of a pressure vessel?
Answer: It is designed to hold gases or liquids at a pressure different from ambient pressure, often used in industrial processes.