Matter and Materials Flashcards
Density definition
density is mass per unit volume
Density formula,
in words
in symbols
density = mass / volume
ρ = m / V
Pressure definition
the normal (or perpendicular) force acting per unit cross-sectional area
Pressure formula,
in words
in symbols
pressure = normal force / cross-sectional area
p = F / A
Change in pressure formula,
in words
in symbols
change in pressure =
density x acceleration due to gravity x depth
∆p = ρgh
Archimedes’ principle definition
the upthrust acting on a body is equal to the weight of the liquid or gas that it displaces
Upthrust formula,
in words
in symbols
upthrust = weight of liquid displaced
upthrust = ρgV
Compressive definition
describes the force that squeezes and shortens an object
Tensile
associated with tension or pulling, for example a tensile force
Extension definition
the increase in the length of a material from its original length
Spring constant definition
the force per unit extension for a spring, unit is Nm^-1
Spring constant formula,
in words
in symbols
spring constant = force / extension
k = F / x
Hooke’s law definition
provided the elastic limit is not exceeded, the extension of an object is proportional to the applied force (load)
Elastic deformation definition
an object that returns to its initial length when the force is removed has deformed elastically
Plastic deformation definition
an object that does not return to its initial length when force is removed is deformed permanently, it has deformed plastically
Limit of proportionality definition
the point beyond which the extension (of a spring) is no longer proportional to the force
Elastic limit definition
the value of stress beyond which an object (such as a spring) will not return to its original dimensions
Strain formula,
in words
in symbols
strain = extension / original length
ε = x / L
Strain definition
extension per unit length
Stress definition
force per unit cross-sectional area that acta at right angles to a surface
Stress formula,
in words
in symbols
stress = normal force / cross-sectional area
ε = F / A
Young modulus definition
the stress in the material divided by the strain
Young modulus formula,
in words
in symbols
young modulus = stress / strain
E = σ / ε
Elastic potential / Strain energy definition
energy stored in a body due to a change in its shape
Work done definition
the product of the force and the distance moved in the direction of the force, the area under a force-extension graph
Elastic potential energy formula x2
E = 1/2 • F • x
E = 1/2 • k • x^2
