Continuing with our important academic questions for the MBA interview series, we will now be covering the Engineering Subjects. Mechanical Engineering Interview Questions & Concepts are critical for aspirants with an engineering background. Mechanical Engineering is one of the oldest and broadest fields of engineering, encompassing the design, analysis, manufacturing, and maintenance of mechanical systems. Below are some of the commonly asked questions and important topics that you should be familiar with. If you would like to read more about domain/academic-specific questions check: Marketing, Economics, Commerce

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Important Mechanical Engineering Interview Questions & Concepts

These are some basic concepts that we have explained. If you already have good knowledge about these, scroll down to Previously asked Mechinal Questions in MBA PI

Thermodynamics

Thermodynamics is the backbone of energy-related systems.

First Law of Thermodynamics: This is essentially the principle of conservation of energy. It states that energy cannot be created or destroyed, only converted from one form to another. For example, in an internal combustion engine, chemical energy from fuel is converted into mechanical work and heat.

Second Law of Thermodynamics: This law introduces the concept of entropy, a measure of disorder. It states that in any energy exchange, the total entropy of a system and its surroundings tends to increase. This law explains why no engine can be 100% efficient.

Heat Transfer:

Conduction: Heat transfer through a solid material (e.g., heat moving through a metal rod).
Convection: Heat transfer through fluids (liquids and gases) due to the movement of molecules (e.g., boiling water).
Radiation: Heat transfer through electromagnetic waves (e.g., heat from the sun).

Thermodynamic Cycles: These are a series of processes that convert heat into work or vice versa. For example:

Carnot Cycle: An ideal cycle that provides the maximum possible efficiency for a heat engine.
Rankine Cycle: Used in power plants to convert heat into work via steam turbines.
Brayton Cycle: Used in gas turbines and jet engines.

Mechanics of Materials

This field focuses on how materials deform and fail under various loads:

Stress and Strain:

Stress is the internal resistance of a material to deformation (measured in Pascals, Pa).
Strain is the deformation of a material relative to its original size (dimensionless)

Elasticity and Plasticity:

Elasticity refers to a material’s ability to return to its original shape after deformation (e.g., a spring).
Plasticity refers to permanent deformation after the load is removed (e.g., bending a metal rod).

Failure Theories: These predict when a material will fail under complex stress conditions:

Maximum Normal Stress Theory: Failure occurs when the maximum normal stress exceeds the material’s strength.
Von Mises Stress Theory: Used for ductile materials, it considers the distortion energy.
Tresca Theory: Based on maximum shear stress.

Beam Bending and Deflection: Beams are structural elements that resist loads applied perpendicular to their axis. Key concepts include:

Moment of Inertia: A measure of a beam’s resistance to bending.
Shear Force and Bending Moment Diagrams: Graphical representations of internal forces in a beam.

Fluid Mechanics

Fluid mechanics deals with the behavior of fluids at rest and in motion:

Bernoulli’s Equation: This principle states that in a steady, incompressible flow, the total energy (pressure energy, kinetic energy, and potential energy) remains constant. It’s used to analyze fluid flow in pipes and aerodynamics.

Reynolds Number: A dimensionless number that predicts flow patterns:

Laminar Flow: Smooth, orderly flow (low Reynolds number).
Turbulent Flow: Chaotic, irregular flow (high Reynolds number).

Pascal’s Law: In a confined fluid, pressure applied at one point is transmitted equally in all directions. This principle is used in hydraulic systems like brakes and lifts.

Hydraulic Systems transmit power using pressurized fluids. Key components include pumps, cylinders, and valves.

Manufacturing Processes

Manufacturing processes transform raw materials into finished products:

Machining: Processes like turning, milling, and drilling remove material to shape a part.

Casting and Molding:

Casting: Pouring molten metal into a mold to create a shape (e.g., engine blocks).
Injection Molding: Forcing molten plastic into a mold (e.g., plastic parts).

Joining Processes:

Welding: Fusing materials using heat (e.g., joining metal plates).
Brazing and Soldering: Joining metals using a filler material with a lower melting point.

Additive Manufacturing (3D Printing): Building parts layer by layer using materials like plastics, metals, or ceramics.

Machine Design

Machine design involves creating components and systems that meet functional requirements:

Design for Manufacturability (DFM): Designing parts that are easy and cost-effective to produce.

Factor of Safety: A ratio of the material’s strength to the maximum expected stress. It ensures reliability under unexpected loads.

Gears and Bearings:

Gears: Transmit power and motion between shafts (e.g., spur gears, helical gears).
Bearings: Reduce friction between moving parts (e.g., ball bearings, roller bearings).

Finite Element Analysis (FEA): A computational tool used to simulate and analyze stresses, strains, and deformations in complex structures.

Dynamics and Kinematics

These fields study motion and the forces that cause it:

Newton’s Laws of Motion:

First Law: An object remains at rest or in uniform motion unless acted upon by a force.
Second Law: Force equals mass times acceleration (F = ma).
Third Law: For every action, there is an equal and opposite reaction.

Kinematic Equations: Describe motion without considering forces (e.g., displacement, velocity, and acceleration).

Vibration Analysis: Studies oscillatory motion and its effects on systems (e.g., resonance in bridges).

Mechanisms: Devices that transmit motion and force (e.g., four-bar linkages in car suspensions).

Control Systems

Control systems regulate the behavior of dynamic systems:

Feedback Control:

Open-Loop Systems: No feedback (e.g., a toaster).
Closed-Loop Systems: Use feedback to adjust performance (e.g., a thermostat).

PID Controllers: Proportional-integral-derivative controllers are used to maintain desired output levels (e.g., temperature control in industrial processes).

Transfer Functions: Mathematical models that describe the input-output relationship of a system.

Stability Analysis: Ensures systems respond predictably to inputs without oscillating or diverging.

Materials Science

Materials science focuses on the properties and applications of materials:

Material Properties:

Strength: Ability to withstand loads.
Hardness: Resistance to deformation or scratching.
Ductility: Ability to deform under tension (e.g., stretching a metal wire).
Toughness: Ability to absorb energy without fracturing.

Phase Diagrams: Graphical representations of the phases of a material at different temperatures and compositions.

Heat Treatment: Processes like annealing (softening), quenching (rapid cooling), and tempering (improving toughness).

Composites and Polymers: Lightweight materials with high strength-to-weight ratios (e.g., carbon fiber composites, plastics).

Heat Exchangers and HVAC Systems

These systems are critical for thermal management:

Types of Heat Exchangers:

Shell and Tube: Used in power plants and refineries.
Plate Heat Exchangers: Compact and efficient for liquid-to-liquid heat transfer.

Refrigeration Cycle: A vapor-compression cycle used in air conditioners and refrigerators. Key components include the compressor, condenser, evaporator, and expansion valve.

Psychrometrics: The study of air and water vapor mixtures, used in designing HVAC systems.

Previously asked Mechanical Engineering Questions in MBA Interviews

Explain a gyroscope.
Draw the phase diagram of Iron and Steel and explain the difference between Cast Iron and Steel.
What are the types of fuel injection systems used in automobiles?
What is ABS in automobiles? Difference between power and torque? Why are gears used in automobiles?
Explain ductility and malleability.
What do you know about Industrial Automation 4.0?
Can you explain the Refrigeration Cycle and Carnot Cycle?
Differentiate between vapor compression and vapor absorption cycle/ Explain the two.
What is annealing and normalizing? Explain the differences.
How would you explain the principle of the rocket engine to a layman? / Explain the principle of a rocket engine.
How do safety standards affect a product's manufacturing design?
What is meant by destructive and non-destructive testing?
What is Young's modulus of elasticity? Is stress a destructive test or a non-destructive one?
Can you show me by drawing the diagram of an IC engine?
Draw the free-body diagram of a car and explain the forces acting on it.
How can AI and robotics impact manufacturing processes?
Units of viscosity.
Explain the difference between a turbine and a pump.
Describe the function of a gearbox.
Hooke’s Principle
Define enthalpy.
Explain heat transfer and mass transfer with the help of examples.
Explain the cooling system in cars.
Tell us about different types of lubrication systems.
What is HVAC and HVDC?
What are the important characteristics of a lubricant?
Difference between engine oil and gear oil.
What is fatigue in the context of material?
What is high-grade energy and low-grade energy? What is a Perpetual Moving Machine of type 2?
Differentiate 2-stroke vs 4-stroke engines.
How to calculate the efficiency of a machine?
Bernaoulli’s theorem and its applications.
Driverless cars and their fallacies
Explain the function of the clutch in a car.
What are your views on hydrogen-fueled cars?
What are your views on electric cars and vehicles?
Why does sound require a medium? How does sound propagate?
What is an open system and a closed system? Give examples of open and closed systems.
What is a gear ratio?
What is entropy? Does it decrease? If we increase the AC temperature, will the entropy increase/decrease?
Differentiate between turbine and compressor.
Difference between Mini Buses and Large Buses from an engineering point of view.
Define torque.
Does IoT influence mechanical engineering? How?
What are the challenges faced by aerospace engineers? Can you suggest any improvements?
Describe CAD and its applications in mechanical engineering.
Differentiate between power and torque.
Please prepare basic trigonometry graphs
Is there a difference between engine oil and gear oil? Explain.
Do you think driverless cars can have a future in India?
What is your take on the future of 3-D printing?

Written by Himanka Parashar. Connect with the author on LinkedIn

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Himanka Parashar

Important Mechanical Engineering Concepts and Questions for MBA Interviews