Theory Examination (Semester-II) 2015-16 ENGINEERING MECHANICS

This question paper tests a student’s understanding of statics, dynamics, strength of materials, torsion, trusses, friction, centroid, and moment of inertia.
The paper is divided into three sections.

SECTION – A (10 × 2 = 20 Marks)

This section contains 10 short conceptual questions based on:

Varignon’s theorem and friction

Law of transmissibility of forces

Relation between load–shear force–bending moment

Assumptions in truss analysis

Bending moment in a simply supported beam

Polar moment of inertia, radius of gyration

Elastic constants

Section modulus

Conservation of energy

These questions test fundamental theory and definitions.

SECTION – B (5 × 10 = 50 Marks)

This section contains choice-based analytical and numerical problems, including:

Reactions on smooth cylinders in a channel

Least force required to move connected blocks with friction

Truss analysis (member forces & nature)

Centroid of a shaded area

Mass moment of inertia of a sphere

Free-fall motion ratios

Motion of a cylinder unwinding from a cord

Strongest beam section from a circular log

This section evaluates problem-solving, diagram interpretation, engineering reasoning, and mathematical calculations.

SECTION – C (2 × 15 = 30 Marks)

This section contains long, detailed questions on:

1. Torsion

Assumptions in torsion theory

Derivation of torsion equation: T/J = τ/r = Gθ/L

Numerical on shaft diameter, twist, and maximum shear stress

2. Beams

Shear Force Diagram (SFD)

Bending Moment Diagram (BMD)

Location of point of contraflexure

3. Moment of Inertia

Moment of inertia of a composite section about centroidal axis

This section tests deep understanding, derivations, and beam/shaft design analysis.