OCR A Physics A-level Topic 3.4: Materials

Flashcards covering key vocabulary and concepts from the lecture notes on materials, focusing on springs, deformation, Hooke's law, force-extension graphs, and mechanical properties like stress, strain, and Young's modulus.

Tensile forces

Forces acting away from the centre of the spring that stretch it out.

Extension

The stretching out of a spring due to tensile forces.

Compressive forces

Forces acting towards the centre of the spring that shorten it.

Compressive deformation

The shortening of a spring due to compressive forces.

Hooke’s law

For a material within its elastic limit, the force applied is directly proportional to the extension of the material.

Force constant (k)

A measure of stiffness of a material.

Elastic deformation

Deformation where the material will return to its original shape when the force is removed.

Plastic deformation

Deformation where the material experiences permanent deformation and will not return to its original length.

Hysteresis loop

A loop on a force-extension graph for rubber, representing the energy lost as thermal energy.

Limit of proportionality (P)

The point up to which Hooke's law is obeyed on a stress-strain graph.

Elastic limit (E)

The point beyond which a material will experience plastic deformation on a stress-strain graph.

Yield points (Y1 and Y2)

Points on a stress-strain graph where there is rapid extension.

Ultimate tensile strength (UTS)

The maximum breaking stress that can be applied to a wire.

Tensile stress (σ)

The force applied to a material per unit cross-sectional area.

Tensile strain (ε)

The extension or compression of a material per unit of its original length.

Young modulus (E)

The ratio of stress to strain; a measure of a material’s stiffness.