Preliminary Engineering Studies Lecture Notes

Comprehensive vocabulary flashcards covering engineering fundamentals, materials, mechanics, braking systems, and biomedical engineering based on the provided lecture notes.

Newton’s 1st Law

A body will remain at rest or at constant velocity unless acted upon by an unbalanced external force.

Newton’s 2nd Law

A body acted upon by an external unbalanced force will accelerate in proportion to the magnitude of this force in the direction in which it acts, expressed as $F = ma$.

Newton’s 3rd Law

To every action there is an equal and opposite reaction.

Mass

The amount of matter that a body contains, with the SI unit being the kilogram ($kg$).

Force

A push or pull on a body measured in Newtons ($N$).

Weight

A force created by gravity, calculated as the effect of Earth's gravitational force on a body ($W = mg$).

Acceleration due to Gravity ($g$)

The rate at which gravitational force accelerates bodies, specified as $9.8\,ms^{2}$ or $10\,ms^{2}$.

Scalar

Quantities defined by magnitude only, such as distance ($20\,M$), time ($30\,s$), or mass ($22.8\,kg$).

Vector

Quantities defined by both magnitude and direction, such as displacement ($1\,km$ north) or velocity ($27\,ms^{-1}$ west).

Lever

The simplest 'machine' using force acting over a distance to magnify effort via mechanical advantage.

Inclined Plane

A basic ramp that allows a load to be progressively raised in height.

Compounds

A combination of two or more elements combined chemically.

Mixtures

The result of two or more pure substances (elements or compounds) which are mechanically mixed together.

Thermoplastics

Polymers that can be resoftened and reformed because they have covalent bonds and weak secondary bonds between chains.

Thermosets

Polymers that cannot be resoftened by heating once they are formed.

Hardness

The ability of a material to resist scratching, abrasion, or indentation.

Malleability

The ability of a material to be hammered and rolled into thin sheets.

Ductility

The ability of a material to be drawn out into thin wire.

Valence Electrons

Electrons in the outer shell of an atom used in bonding.

Polymorphism (Allotropy)

The ability of a single substance to exist in multiple forms or crystal structures.

Amorphous

Non-crystalline materials without form that lack ordered atomic structure, such as glass, liquids, and gases.

Ferrous Metals

Metals where iron is the primary constituent, such as mild steels and stainless steel.

Brass

An alloy of Copper and Zinc, often containing up to $40\%$ zinc.

Bronze

An alloy of copper and tin.

Casting

A forming process involving heating a material and placing it into a permanent (metal) or disposable (sand) mould.

Extruding

A forming process likened to squeezing toothpaste from a tube, used for items like aluminium window frames.

MIG Welding

Metal Inert Gas welding which uses a continuous feed wire electrode and an inert gas like argon to prevent oxidation.

Tracheids

Cellulose fibres in timber held together by lignin.

Abstract

A clear, concise summary of an engineering report giving the reader a brief explanation of the purpose.

Factor of Safety

A design consideration used by engineers to ensure the final design is safe for production.

Wetware

A resource in project management referring to ideas and thought.

Concurrent Forces

A system of forces that all pass through the same point.

Couple

Two parallel, co-planar forces of the same magnitude and direction but opposite sense that produce rotation but not translation.

Moment of a Force

The actual or potential rotation caused by a force, calculated as $M = Fd$ and measured in Newton metres ($Nm$).

Annealing

A heat process where metal is heated to a specific temperature ($900^{\circ}$) and allowed to cool slowly to soften it.

Quenching

The rapid cooling of a work piece to obtain certain material properties, making steel hard but brittle.

Current ($I$)

The quantity of electrons flowing per second, measured in amperes ($A$).

Potential Difference ($E$)

Measured in volts ($V$), this is the difference between the point where electrons enter a system and where they exit.

Isometric Drawing

A pictorial drawing constructed on a set of three axes at $120^{\circ}$ to one another.

Anti-lock Braking System (ABS)

A safety system that prevents wheels from locking up and avoiding uncontrolled skidding by maintaining tractive contact.

Regenerative Brake

An energy recovery mechanism that slows a vehicle by converting its kinetic energy into a form that can be used or stored.

Stress ($\sigma$)

The relationship between an applied load and a material's cross-sectional area ($P/A$), measured in $MPa$ or $N/mm^{2}$.

Strain

The proportional change in length of a material under an axial load.

Work ($W$)

Occurs when a force causes motion, calculated as $W = F \times s$ and measured in Joules ($J$).

Hooke’s Law

States that stress is proportional to strain up to the elastic limit.

Austenite

A structure of steel formed at $1000^{\circ}C$ with a Face Centred Cubic (FCC) arrangement.

Ferrite

A soft and ductile form of pure iron with a Body Centred Cubic (BCC) structure containing maximum $0.025\%$ carbon.

Pearlite

A finely laminated mixture of ferrite and cementite present in cast iron and steel.

Mechanical Advantage (MA)

The ratio of load to effort in a mechanical system.

Velocity Ratio (VR)

The ratio of the distance the effort moves to the distance the load moves in a mechanical system.

Forging

The process of shaping metal with forceful blows, which can be done hot (above recrystallization temperature) or cold.

Integrated Circuits (ICs)

A miniaturised circuit consisting of resistors, capacitors, transistors, and diodes manufactured onto a single silicon chip.

Logic Gates

Electronic circuits that respond to the logic state (1 for high or 0 for low) of inputs.