Biomechanics 1 Flashcards
The study of the structure and functions of biological systems by means of the methods of mechanics
Biomechanics
Purpose of biomech studies
to apply therapeutics and medical tech pertaining to human body
study of physical actions of forces
mechanics
mechanics consist of?
statics and dynamics
study of systems that are in a constant state of motion, whether at rest with no motion or moving at a constant velocity without acceleration; involves all forces acting on the body being in balance resulting in the body being in equilibrium
biomechanics
study of systems in motion w/acceleration; involves a system in acceleration being unbalanced due to unequal forces acting on the body
dynamics
scalar quantity
has only magnitude. ex: length, area, volume…etc
vector quantity
has both magnitude and direction, ex: velocity, acceleration..etc.
Vector/physical quantity w/c causes or tends to cause a change in the motion or shape of a body
force
properties of force
- magnitude
- direction
- point of application
- line of action
force that presses the ends of bones together and is produced by muscles, weight bearing, gravity, or some external loading down the length of the bone
compressive force
pulling force that creates tension in the object/body and tends to lengthen and narrow; muscle is usually the source
tensile force
Stress that arises from the force vector component parallel to the cross section
shear stress
Stress that arises from the force vector component perpendicular to the cross section
normal stress
load per cross sectional area
stress
deformation w/ respect to the original length
strain
strain that changes in length
normal strain
strain that changes in angle
shear strain
measure of the quantity of matter
mass
measure of force (pull of gravity on mass)
weight
defined as a body or objects resistance to a change in motion
inertia
1st law of motion (inertia)
a body at rest or in a uniform motion will tend to remain at rest or in motion unless acted by an external force or torque
2nd law of motion
a force or torque acting on a body will produce an acceleration proportional to the force or torque (f=ma)
3rd law of motion
for every action there is an equal and opposite reaction (torque and/or force)
vector measurement, the length and direction of a line joining the initial position with the final position
displacement
pressure formula
P= f/a
physical principles influencing pulmonary ventilation
- air flows from areas of higher to lower pressure
- changes in volume result in changes in pressure (Boyle’s law)
- changes in tube diameter result in changes in resistance (Pouseuille’s law)
resistance that a fluid offers to flow when subject to a shear
viscosity
Navier Stokes
if the fluid is incompressible, then inertia becomes and if fluid has no friction, the viscosity becomes 0
