(SEM I) THEORY EXAMINATION 2024-25 FUNDAMENTALS OF MECHANICAL ENGINEERING

This document contains the B.Tech Semester I (2024–25) theory examination for the subject Fundamentals of Mechanical Engineering (BME101).
The paper is structured to test the student’s basic understanding of mechanics, thermodynamics, refrigeration & air-conditioning, hydraulic machines, electric vehicles, and mechatronics systems.
It consists of three sections (A, B, and C), arranged to evaluate conceptual clarity, analytical ability, and engineering problem-solving skills.

SECTION A – Short Answer Questions (Basic Concepts & Fundamentals)

This section includes 7 compulsory questions of 2 marks each, testing essential definitions and direct formulas.

Topics include:

1. Strength of Materials

Stress, yield stress, factor of safety

Comparison of applied stress vs material strength

2. Hybrid Electric Vehicles (HEV)

Key components of HEV drivetrain such as motors, batteries, controllers

3. Refrigeration & Air Conditioning

Calculating Ton of Refrigeration from heat extraction rate

4. Fluid Mechanics

Variation of fluid pressure with depth

Difference between gauge pressure and absolute pressure

5. Measurement Systems

Proving ring and its use in force measurement

6. Mechatronics

Definition and role of an actuation system

This section evaluates K1-level knowledge: definitions, formulas, basic understanding.

SECTION B – Descriptive Questions (Conceptual & Applied Understanding)

Students must attempt any 3 questions, each carrying 7 marks.
These questions require explanation, comparison, and application of engineering principles.

Topics include:

1. Material Behaviour

Comparing ductile vs brittle stress–strain diagrams

Yielding, fracture, elongation

2. Electric Vehicles (EVs)

Use of power electronics like inverters and converters

3. Psychrometrics

Properties such as DBT (Dry Bulb Temperature), WBT (Wet Bulb Temperature), DPT (Dew Point Temperature), and humidity

4. Hydraulic Machines

Differences between Pelton Wheel and Francis Turbine

Efficiency, head, application area

5. Pneumatics

Pneumatic sequencing with real-life examples

This section checks K2-level understanding: explanation, comparison, and conceptual interpretation.

SECTION C – Long Answer Questions (Numerical, Derivation, and Diagram-Based Work)

Section C contains long-answer, analytical, and diagram-based questions, each carrying 7 marks.
Students must attempt one question from each main number (3, 4, 5, 6, and 7).

This section is designed to test higher-level understanding (K2–K3), including engineering drawing, derivations, numerical calculations, comparison of systems, and explanation of mechanical principles.
Below is the description of what the questions cover:

3 – Strength of Materials & Elasticity

This question evaluates the student's understanding of structural analysis and material mechanics.

3(a) Cantilever Beam Analysis

Drawing the Free Body Diagram (FBD) of a 4 m cantilever beam

Beam loaded with:
• UDL = 15 kN/m
• Point load = 20 kN at free end

Objective: Calculate support reactions (shear force & bending moment) at the fixed end

This tests the ability to analyze static loads on beams.

3(b) Relation Between Elastic Constants

Derivation of relationship between:
E (Young’s Modulus), G (Shear Modulus), K (Bulk Modulus), ν (Poisson’s Ratio)

Understanding of how elastic constants interrelate in isotropic materials

This tests conceptual understanding of material elasticity.

4 – EV Technology & IC Engines

This question covers electric vehicles and internal combustion engines.

4(a) EV Charging System

Description of EV charging components:
Charger, battery pack, controller, rectifier

Comparison:
Fast charging vs slow charging (speed, cost, battery impact, use cases)

4(b) Four-Stroke CI Engine

Construction details:
Cylinder, piston, crankshaft, valves, injector

Working principle of 4 strokes:
Suction → Compression → Power → Exhaust

Neat labeled diagram required

This tests understanding of both modern EV systems and conventional engines.

5 – Refrigeration & Air Conditioning

This question focuses on performance analysis and comparison.

5(a) Air Conditioning Performance

Factors:
Heat load, ambient temperature, insulation, airflow, humidity control

Optimization methods:
Proper refrigerant charge, efficient compressor, clean filters, duct design

5(b) Heat Pump vs Refrigerator

Comparison based on:
Working cycle, direction of heat transfer, COP (Coefficient of Performance), applications

This evaluates thermodynamic system understanding.

6 – Fluid Mechanics & Hydraulic Machines

This question examines concepts of fluid flow and machine performance.

6(a) Bernoulli’s Principle

Explanation of pressure–velocity relationship in a fluid

How pressure decreases when velocity increases and vice versa

Application in pipes, nozzles, and venturi meters

6(b) Pump and Turbine Performance Factors

Factors:
Cavitation, flow rate, head, rotational speed, friction, design efficiency

Impact on output and performance

This tests applied understanding of fluid systems.

7 – Mechanisms & Machines

This question focuses on mechanical motion transmission mechanisms.

7(a) Ratchet Mechanism

Labeled diagram

Working: allowing motion in one direction, restricting in reverse

Applications:
Jack lifts, clocks, wrenches, indexing mechanisms

7(b) Cam Mechanism

Neat labeled diagram

Cam–follower motion

Stroke, dwell, return phases

Real-world uses in engines, automation systems

This tests visualization and understanding of machine components.

Summary of Topics Covered

The question paper examines understanding in the following major engineering domains:

Strength of materials & mechanics

Fluid mechanics & Bernoulli’s principle

Refrigeration, air-conditioning, and psychrometrics

Electric vehicles & power electronics

Hydraulic turbines & pumps

IC engines (four-stroke diesel)

Mechatronics, actuation, and measurement systems

Engineering mechanisms (cam, ratchet)

It is designed to test both conceptual clarity and analytical skills, ensuring students grasp the foundational principles of mechanical engineering.