Reference
Mechanical engineering glossary
A compact reference for the core terms that appear across the roadmap. Each definition focuses on what the concept means, where it is used and what students commonly confuse.
Free-body diagram
A diagram of one isolated body showing all external forces and moments acting on it. It is the starting point for equilibrium equations in statics and dynamics.
Course link: Statics
Equilibrium
A state where the resultant force and, for rigid bodies, the resultant moment are zero. In 2D statics: ΣFx=0, ΣFy=0 and ΣM=0.
Common confusion: equilibrium does not mean “no forces”; it means forces balance.
Stress
Internal force intensity inside a material. Normal stress is commonly written as σ = F/A for a uniform axial load.
Course link: Mechanics of Materials
Strain
Relative deformation. Engineering normal strain is often written as ε = ΔL/L, describing change in length divided by original length.
Entropy
A thermodynamic property used to evaluate irreversibility, heat transfer and the direction of real processes. It is central to the second law of thermodynamics.
Course link: Thermodynamics
Reynolds number
A dimensionless ratio comparing inertial and viscous effects in fluid flow. It helps classify flow regimes and judge dynamic similarity.
Re = ρVD/μ
Thermal resistance
A modelling idea that treats heat flow like current through a resistance. It is useful for conduction, convection and combined heat-transfer networks.
Course link: Heat Transfer
Transfer function
A frequency-domain or Laplace-domain representation of how a linear system transforms input into output under zero initial conditions.
Course link: System Dynamics and Control
Tolerance
The allowable variation in a dimension or geometric feature. Tolerances connect design intent to manufacturing, inspection and cost.
Course link: Engineering Graphics, Sketching and CAD
Mesh convergence
A numerical verification check in FEA or CFD: refine the mesh and verify that the result approaches a stable value rather than changing arbitrarily.
Course link: Finite Element Methods
Verification and validation
Verification asks whether the model was solved correctly. Validation asks whether the model represents reality well enough for the intended decision.
Factor of safety
A design margin comparing capacity to demand. It accounts for uncertainty in loads, materials, modelling assumptions, manufacturing and use conditions.
FoS = capacity / demand
Next step
Use the glossary with the roadmap.
Look up terms as you study, but let the roadmap decide what to learn next.