AMIE Section A Examination key terms

Internal force per unit area within a material that arises in response to an applied load, typically measured in pascals or megapascals.

The fractional change in length or shape of a material caused by an applied stress, expressed as a dimensionless ratio.

A measure of the stiffness of a solid material, defined as the ratio of tensile stress to tensile strain in the linear elastic region.

The ratio of a structure's or material's ultimate strength to the actual working stress, used to ensure safe design under uncertainties.

The stress at which a material begins to deform plastically, meaning it will not return to its original shape when the load is removed.

A twisting force that tends to cause rotation, calculated as the product of force and the perpendicular distance from the pivot.

The turning effect of a force about a point, equal to the force multiplied by the perpendicular distance from the point to the force's line of action.

A state in which the net force and net moment acting on a body are both zero, so the body remains at rest or moves with constant velocity.

A sketch showing all external forces acting on an isolated body, used to apply equilibrium equations and solve for unknown reactions.

A principle stating that for steady, incompressible, frictionless flow, the sum of pressure energy, kinetic energy, and potential energy per unit volume is constant along a streamline.

A statement of conservation of mass for fluid flow, meaning the mass flow rate into a control volume equals the mass flow rate out under steady conditions.

A dimensionless quantity that predicts flow regime by comparing inertial forces to viscous forces; low values indicate laminar flow, high values turbulent flow.

A material property describing the rate at which heat passes through a unit thickness for a unit temperature difference across a unit area.

A measure of the convective heat transfer between a fluid and a solid surface, defined as heat flux per unit temperature difference.

The amount of heat energy required to raise the temperature of one kilogram of a substance by one kelvin, measured in joules per kilogram-kelvin.

A fundamental electrical principle stating that the current through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance.

Two rules for circuit analysis: the current law states that current into a junction equals current out, and the voltage law states that voltages around a closed loop sum to zero.

The rate at which electrical energy is transferred by a circuit, calculated as the product of voltage and current, measured in watts.

A graph plotting stress against strain for a material, revealing its elastic limit, yield point, ultimate strength, and fracture behavior.

The principle that the deformation of an elastic material is directly proportional to the applied load, valid up to the material's elastic limit.

The principle that a pressure change applied to an enclosed fluid is transmitted undiminished to every part of the fluid and the container walls.

The law stating that the buoyant force on an object submerged in a fluid equals the weight of the fluid displaced by that object.

The maximum theoretical efficiency of a heat engine operating between two temperatures, calculated as one minus the cold temperature divided by the hot temperature in kelvin.

A measure of the disorder or randomness in a system; in thermodynamics, it quantifies the energy unavailable to do useful work and always increases in isolated systems.

The principle that the rate of heat conduction through a material is proportional to the negative temperature gradient and the cross-sectional area.

The principle that the rate of heat loss from a body is proportional to the temperature difference between the body and its surroundings.

The curved path of an object thrown into the air, subject only to gravity, where horizontal and vertical motions are independent and combine to form a parabola.

Three foundational principles of motion: objects remain at rest or in uniform motion unless acted upon by a force; force equals mass times acceleration; and every action has an equal and opposite reaction.

The branch of mechanics that describes the motion of objects using displacement, velocity, acceleration, and time, without considering the forces causing the motion.

The principle that the net work done on an object equals its change in kinetic energy, linking force and displacement to speed changes.

The principle that energy cannot be created or destroyed but only transformed from one form to another, so the total energy of an isolated system remains constant.

A measure of an object's resistance to rotational acceleration about an axis, depending on its mass distribution relative to that axis.

A phenomenon where a system oscillates with large amplitude when driven at its natural frequency, potentially causing excessive vibration or structural failure.

The weakening and eventual failure of a material caused by repeated or fluctuating stress cycles, even when the maximum stress is below the yield strength.

The slow, permanent deformation of a material under a constant load sustained over a long period, especially at elevated temperatures.

A sudden sideways failure of a slender structural member under compressive load, occurring when the load exceeds a critical value.

A material's resistance to indentation, scratching, or abrasion, often measured by standardized tests such as Brinell or Rockwell.

The ability of a material to undergo significant plastic deformation before fracture, allowing it to be drawn into wires or shaped without breaking.