3.4 - materials Flashcards
what is hookes law
when a spring is stretched the force is directly proportional to the extension until the limit of proportionality is reached
what does a high spring constant value indicate
a stiff spring
on a force extension graph, what is the spring constant
the gradient
on a force extension graph what does obeying hookes law look like
a straight line through the origin
what do you do to the total spring constant when springs are in parallel
add them
what do you do to the spring constant when the springs are in series to find the total spring constant
1/k(total) = 1/k(1) + 1/k(2)
in a force extension graph or a force displacement graph what is the area under the graph
the work done / energy transferred
what is the limit of proportionality on a force extension graph
the point where force and extension are no longer directly proportional
what is the elastic limit on a force extension graph
the point where an object will start to return to its original shape but not return completely
what is the yield point on a force extension graph
when an elastic object becomes plastic
what does brittle mean
objects will undergo little plastic deformation before breaking
what does stiffness mean
a material exhibits little deformation even when subject to large forces
what does hardness mean
materials ability to absorb impacts without breaking
what does strength mean
an objects ability to withstand large forces without breaking
what does it mean if an object is malleable
the ability for an object to be hammered into sheets
what does it mean if an object is ductile
it is easy to draw out eg. into wires
what is tensile deformation
deformation by a pulling or stretching force
what is compression deformation
deformation by a crushing or compressive force
what is stress measure in
pascals
what is the unit of strain
has no unit
what is the unit of young modulus
pascals
what is the young modulus
how stiff an object is
