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46 Cards in this Set
- Front
- Back
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which forces do not affect the motion of the whole body?
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internal forces
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what is a distraction force?
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pull of one bony segment away from another
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what is a compression force?
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push of one bony segment toward another
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What is a shear force?
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pull or push perpendicular to distraction or compression forces
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what is the primary non-contact force to consider?
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gravity
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weight always?
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acts down toward the center of the earth
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center of mass?
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point where weight force can be considered to act on the body where all 3 planes intersect
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what is normal force?
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force pressing 2 surfaces together
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what is the coefficient of friction?
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types of surfaces in contact with each other
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what is the friction force?
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Fn * u
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What is Newton's first law?
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Law of Inertia
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What is Newton's second law?
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Law of Acceleration
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What is Newton's third law?
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Law of Action and reaction
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Law of inertia states?
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body in motion will tend to remain in motion; body at rest will remain at rest
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law of inertia refers to a state where?
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1. no external forces on an object
2. net external forces are zero |
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According to the law of acceleration the change of motion of an object is?
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1. proportional to net external force
2. in direction of this force |
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Law of action-reaction states?
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every action there is an equal and opposite reaction.
force that is exerted on one body by another, there is an equal and opposite force exerted by the second body on the first. |
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Newton's second law for linear and angular?
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F = m * a
T = l * angular acceleration |
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Torque
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influence on a body or system, producing or tending to produce a change in angular movement
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objects fixed in space at a certain point will?
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rotate about that point
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collagen fibers?
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strong and resistant to stretch
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elastic fibers?
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weak and application of force causes stretch
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ligaments
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1. bone to bone
2. prone to sprains 3. more elastic than tendon |
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tendons?
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1. less elastic than ligaments
2. muscle to bone 3. transfer forces from muscle to bone |
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hooke's spring law
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F = stiffness * distance stretched
store and return mechanical energy |
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cortical bone?
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provides majority of stretch and stiffness
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cancellous bone?
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lighter, but able to bear load
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fractures occur when?
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loading to failure
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Wolff's Law states that?
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remodeling of bone occurs in response to physical stress
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stress ?
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force / CSA
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load deformation curve which region acts like a perfect spring?
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elastic region
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past yield point get?
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in plastic region and get a permanent change
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which region in the load deformation curve allows to achieve for ROM
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plastic stage
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efferent (motor)
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from CNS to muscle
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afferent (sensory)
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from periphery to CNS
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sliding filament model
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1. release Ca2+ expose binding site
2. power stroke- slide past ea other 3. ATP binds to myosin releasing actin 4. ATP hydrolyzed, myosin head return to resting position |
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temporal summation
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1 motor unit; caused by a single impulse of force
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spatial summation
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from different areas
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type 1 muscle fiber composition
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slow, small, fatigue resistant
(endurance, postural muscles) |
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type 2 muscle fiber composition
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fast, medium, fatigue resistant
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type 3 muscle fiber composition
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fast, large, fatigable
(explosive actions, doesn't produce force for a long time but produces a lot of force |
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concentric muscle contractions
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muscle shortens while producing force
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isometric muscle contractions
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muscle stays the same length while producing force
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eccentric muscle contractions
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muscle lengthens while producing force
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fusiform
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long, parallel fibers
low force, high displacement and velocity |
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penniform
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shorter, fan-like fibers
high force, low displacement and velocity |
