improving our knowledge of the human body so we may then apply this knowledge to make our movements more efficient and combat those forces that may cause pathological conditions or injury
what are the principles of statics?
analyzs the magnitude and nature of forces that occur at the joint and muscle level, it determines the effort required for certain muscle groups to hold a specific joint or body part in posistion
What are the principles of dynamics?
analyzes the motion of the static system during such movements as gait and has many applications in sports mechanics
What are the mechanics of solids?
provides the necessary tools for developing the field of consititutive equations for biological systems that are used to evaluate their functional behavior under different load conditions
What are the priciples of fluid mechanics?
have been used to determine blood flow through the circulatory system, airflow in the lungs and the release of synovial fluid for joint lubrication
what are scalar quantities?
have magnitude such as mass, energy and power
what are vector quantities?
have magnitude and direction such as force, movement and acceleration and graphically represented by an arrow which determines the direction
what is a force vector?
a force is a mechanical disturbance such as the white pool ball creating a force vector when it hits the black 8 ball or pitched ball hits a catchers mitt
what is a torque vector?
the rotational and twisting action of applied forces, an example is when someone opens a door on a hinge
what is a moment vector?
the bending action that occurs with applied forces, someone jumping on a diving board
how do you measure the magnitude of torque?
M=DF, F is the magnitude of the force, d is the distance between the axis and the extended line of the force or lever arm, M is the magnitude of the moment
what does the free body diagram do?
assists in identifying the ofrces and moments acting on individual parts of the system and ensure correct use of equations of mechanics
what is deformation?
local shape change under the effect of applied forces
what is tension?
occurs when the object elongates, axial
what is compression?
when the object shrunks, axial
what is stress?
the intensity of an internal distributed force
what is strain?
a measure of degree of deformation
what is shear loading?
is caused by forces acting in the directions tangent tothe area resisting the forces causing shear, tangential; breaking a pencil
what is elasticity?
the ability of a material to resume its original size, shape on removal of applied loads
what is plasticity?
a permanent deformation of an object
what is viscoelasticity?
the characteristic of a material that has both fluid and solid properties, viscoelastric materials are dependent upon how quickly loads are applied or removed and are time dependent
are elastic materials time dependent?
if a material is more solid then the deformation will
be fully recoverd
if the viscoelasrticmaterial is more liquid then
there will always be a residue of deformation left in the material
what is a creep and recovery test?
load on a material, maintain the load at a constant level for a period of time, remove the load and observe material response
what is creep?
term used to descrive the tendency of a solid material to slowly move or deform permanently to relieve stresses. it occurs as a result of long term exposure to levels of stress that are below the yield strength or ultimate strength of material
is creep deformation time dependent?
what is a stress relaxation experiment?
conducted by straining the material to a level and maintaing a constant strain while observing the stress response to the material
what will elastic material do with stress relaxation
what will a viscoelastic solid do in stress relaxation
will respond with an initial high stress that wull decrease over time but the stress will never reduce to zero
what will viscoelastic fluid do in stress relaxation?
reduce to zero
fracture from repeated loading is called?
fatigue, the material can only hold so much before it compromises
the stress at which the fatigue levels off preventing possible fracture is
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