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Glossary

# Glossary

deformation
change in shape due to the application of force
drag force
$FDFD size 12{F rSub { size 8{D} } } {}$, found to be proportional to the square of the speed of the object; mathematically
5.48 $FD∝v2FD∝v2 size 12{F rSub { size 8{D} } prop `v rSup { size 8{2} } } {}$
5.49 $FD=12CρAv2,FD=12CρAv2, size 12{F rSub { size 8{D} } = { {1} over {2} } Cρ ital "Av" rSup { size 8{2} } } {}$
where $CC size 12{C} {}$ is the drag coefficient, $AA size 12{A} {}$ is the area of the object facing the fluid, and $ρρ size 12{ρ} {}$ is the density of the fluid
friction
a force that opposes relative motion or attempts at motion between systems in contact
Hooke's law
proportional relationship between the force $FF$ on a material and the deformation $ΔLΔL$ it causes, $F=kΔLF=kΔL size 12{F=kΔL} {}$
kinetic friction
a force that opposes the motion of two systems that are in contact and moving relative to one another
magnitude of kinetic friction
$fk=μkNfk=μkN size 12{f rSub { size 8{k} } =μ rSub { size 8{k} } N} {}$, where $μkμk size 12{μ rSub { size 8{K} } } {}$ is the coefficient of kinetic friction
magnitude of static friction
$fs≤μsNfs≤μsN size 12{f rSub { size 8{s} } <= μ rSub { size 8{s} } N} {}$, where $μsμs$ is the coefficient of static friction and $NN$ is the magnitude of the normal force
shear deformation
deformation perpendicular to the original length of an object
static friction
a force that opposes the motion of two systems that are in contact and are not moving relative to one another
Stokes' law
$Fs=6πrηvFs=6πrηv size 12{F rSub { size 8{s} } =6πrηv} {}$, where $rr$ is the radius of the object, $ηη$ is the viscosity of the fluid, and $vv$ is the object's velocity
strain
ratio of change in length to original length
stress
ratio of force to area
tensile strength
measure of deformation for a given tension or compression