Topic 5 - Materials Flashcards
Brittle
Snaps without stretching or bending when subject to stress.
Density of a substance
Mass per unit volume of the substance
Ductile
Stretches easily without breaking.
Elastic limit
Point beyond which a wire is permanently stretched.
Elasticity
Property of a solid that enables it to regain its shape after it has been deformed or distorted.
Hooke’s law
The extension of a spring is proportional to the force needed to extend it.
Limit of proportionality
The limit beyond which, when a wire or spring is stretched, it’s extension is no longer proportional to the force that stretches it.
Pascal
Unit of pressure or stress equal to 1 N/m
Plastic deformation
Deformation of a solid beyond it’s elastic limit.
Stiffness constant
The force per unit extension needed to extend a wire or a spring.
Strain
Extension per unit length of a solid when deformed.
Stress
Force per unit area of cross-section in a solid perpendicular to the cross-section.
Ultimate tensile stress
Tensile stress needed to break a solid material.
Yield point
Point at which the stress in a wire suddenly drops when the wire is subjected to increasing strain.
Young modulus
Stress/strain (assuming the limit of proportionality has not been exceeded)
