Term
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Definition
SHORTEST DISTANCE BETWEEN FORCE VECTOR AND COR
PERPENDICULAR TO FORCE VECTOR |
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Term
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Definition
ARE PARALLEL
ARE EQUAL in MAGNITUDE, BUT OPPOSITE IN DIRECTION
HAVE EQUAL MOMENT ARMS
RESULTS IN: PURE ROTATION WITH NO TRANSLATION |
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Term
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Definition
AN OBJECT WILL REMAIN AT REST OR CONTINUE MOVING AT A CONSTANT VELOCITY UNLESS ACTED UPON BY AN UNBALANCED EXTERNAL FORCE
SUM OF FORCES = 0
SUM OF MOMENTS = 0 |
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Term
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Definition
IF THERE IS AN UNBALANCED FORCES ACTING ON A OBJECT, IT WILL PRODUCE AN ACCELERATION IN THE DIRECTION OF THE FORCE, DIRECTLY PROP0RTIONAL TO THE FORCE.
F=MA |
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Term
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Definition
| FOR EVERY ACTION THERE IS A REACTION OF EQUAL MAGNITUDE BUT IN THE OPPOSITE DIRECTION |
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Term
| STATIC EQUILIBRIUM (2D ANALYSIS) |
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Definition
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Term
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Definition
| MUSCLE AND RESISTIVE FORCES ON OPPOSITE SIDE OF COR |
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Term
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Definition
MUSCLE AND RESISTIVE FORCES ON SAME SIDE OF COR
RESISTIVE FORCE IS CLOSER TO COR |
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Term
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Definition
MUSCLE AND RESISTIVE FORCES ON SAME SIDE OF COR
MUSCLE FORCE CLOSER TO COR |
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Term
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Definition
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Term
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Definition
POINT ABOUT WHICH THE BODY'S MASS IS EVELY DISTRIBUTED
POINT ABOUT WHICH THE SUM OF THE TORQUES DUE TO GRAVITY EQUAL ZERO
POINT WITHIN A SEGMENT THAT CREATES THE SAME NET MOMENT ABOUT ANY POINT ALONG THE SEGMENT AXIS AS DID THE ORIGINAL MASS. |
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Term
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Definition
| SINGLE MOTOR NEURON AND ALL MUSCLE FIBERS IT INNERVATES |
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Term
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Definition
MEASURE FORCE
PROTECTIVE MECHANISM BUILT IN |
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Term
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Definition
Stretch receptors: muscle spindles
Tension and force: Golgi tendon organs |
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Term
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Definition
Stress/strain
Dependent on the type of material |
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Term
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Definition
Force/Length
Dependent on structural properties |
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Term
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Definition
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Term
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Definition
| This part of the Force-Length the tissue will recover. Tissue is not damaged |
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Term
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Definition
| Once past yield point permanent damage is done. |
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Term
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Definition
| Change in length/original length |
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Term
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Definition
Ration of change in length in one dimension to another
Indicator of volume change
v = 0.5, incompressible- volume stays the same (tendons)
v, 0.5, compressible )bones |
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Term
| Relationship between stiffness (k) and Young's Modulus (E) |
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Definition
Increase length : Decrease k
Increase area : Increase k
Increase Young's Modulus : Increase k |
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Term
| Slope of Force-length curve |
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Definition
Stiffness
Extrinsic stiffness or rigidity
Dependent on material composition and shape |
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Term
| Slope of Stress-Strain Curve |
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Definition
Young's Modulus
Modulus of elasticity or intrinsic stiffness
Dependent on material composition only |
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Term
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Definition
Collagen
Ground Substance
Inorganic Component
Cells
Water |
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Term
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Definition
protein found in most connective tissue
contains wavy fibers that resist stretching |
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Term
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Definition
proteoglycans
cements collagen |
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Term
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Definition
calcium and phosphate embedded in collagen
provides solid consistency |
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Term
| What is responsible for force generation of a muscle? |
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Definition
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Term
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Definition
| young bone forming cells that cause the hard extracellular matrix of bone to develop |
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Term
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Definition
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Term
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Definition
| Mature bone cells that maintain the structure of bone |
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Term
Bone structure
Microstructure |
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Definition
| osteon/haversian system with cylindrical channels |
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Term
Bone Structure
Macrostructure |
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Definition
cortical/compact bone- outer shell
cancellous/trabecular bone- inner more porous
perosteum- fibrous membrane, surrounding bone |
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Term
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Definition
adding more motor units
contributes to modulation of forces |
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Term
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Definition
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Term
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Definition
Loose connective tissue- Random order- Fascia
Dense connective tissue-
Irregular- Random order, periosteum
Regular- parallel fibers(tendon, ligament, aponeurosis)
Cartilage
Bone |
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Term
| Structure of connective tissue |
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Definition
Cells
Extracellular Matrix
-Interfilrillar- ground substance proteoglycans and glycoproteins
-Fibrillar- collagen and elastin
Inorganic matrix
Water |
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Term
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Definition
Ultimate yield is close to yield point
ex. Glass |
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Term
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Definition
ultimate yield far from the yield point
ex. metal |
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Term
| Sub-Failure deformation occurs in the _______ region |
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Definition
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Term
| Post-failure deformation occurs in _________ region |
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Definition
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Term
| How does bone remodel as we age to increase the load we can bear? |
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Definition
Increase cross-sectional area
Change material composition |
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Term
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Definition
tension- calcaneous
compression- vertebrae
bending- "boot top" tibia
shear- tibial plateau
torsion- spiral fracture
break at 45 degrees |
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Term
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Definition
High stiffness
Wolf's Law- bone remodels under loads
Cancellous bone fx at 75% strain, cortical at 2%
Bone is stronger in compression than tension
Bone is anisotropic |
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Term
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Definition
| bone has different material properties depending on what direction it is loaded. |
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Term
| Tendon/ligament composition |
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Definition
Extracellular Matrix-
-collagen(25%)
-elastin
-gound substance- proteoglycans (5%)
Cells-
-fibroblasts
Water- (70%) |
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Term
| Tendon/Ligaments structure |
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Definition
Collagen
Proteoglycans
Elastin |
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Term
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Definition
crimped and with cross links
parallel arrangement in tendons
more mixed arrangement in ligaments |
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Term
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Definition
| binds extracellular water, cement like |
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Term
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Definition
| low concentration except in ligamenta flava |
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Term
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Definition
bone is more linear
bone has a higher E
bone fails at a higher stress
bone fails at a lower strain |
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Term
| Control parameters that affect biomechanics |
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Definition
tissue loading rate
loading vs unloading
number of loading cycles
length of time tissue is held at five force or displacement |
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Term
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Definition
| Stiffness and young's modulus increase with increased loading rate |
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Term
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Definition
Loading and unloading curves are not the same
Viscoelastic tissue means it won't return on the same path |
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Term
| Multiple cycles of loading |
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Definition
| Tissue will stretch (increase length) with multiple loading cycles |
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Term
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Definition
| Force or stress will decrease if length or strain is kept constant |
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Term
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Definition
| Length or strain will increase if force or stress is kept constant |
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Term
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Definition
cells- condrocytes
Extracellular matrix- type II collagen, proteoglycans
Water
Avascular |
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Term
| Hyaline cartilage structure |
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Definition
Biphasic- fluid filled, porous-permeable medium (sponge)
proteoglycans- attracts water, causing swelling
collagen- wavy |
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Term
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Definition
cartilage mainly acts in compression
proteoglycans compress
increase in water pressure
tension load on the collagen and water outflow
Water pressure forces cartilage straight in order to bear the load. |
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Term
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Definition
Creep and stress relaxation very important
Can act as a shock absorber (debatable)
Helps increase surface contact area between surfaces
Can take from 4-16 hours to reach equilibrium |
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Term
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Definition
Vector product
If finish in the same place they started displacement is zero |
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Term
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Definition
Scalar product
How far you traveled |
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Term
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Definition
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Term
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Definition
| Product of mass and velocity |
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Term
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Definition
The total momentum of a system of objects is constant if the net external force acting on the system is zero.
Newton's first Law |
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Term
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Definition
All energy is conserved
No energy lost |
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Term
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Definition
objects combine together
Energy is not conserved
Objects that are moving combine together and move at same velocity after collision
v1
V1=V2 |
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Term
elastic Collision situation
Moving object collides with stationary object |
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Definition
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Term
Elastic collision situation
Head on collision |
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Definition
| Essentially swap momentums |
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Term
Elastic collision equation
Fast moving object collides with slower moving object |
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Definition
| Slower mving object ends up with all of the momentum after the collision |
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Term
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Definition
Product of force and displacement (scalar)
Force and displacement along the same axis
Units- N x m = Joules |
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Term
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Definition
| Force and displacement in the same direction |
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Term
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Definition
| Force and displacement in the opposite direction |
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Term
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Definition
| work done does not depend on path taken |
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Term
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Definition
| work done depends on path |
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Term
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Definition
| W = change in KE + change in PE |
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Term
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Definition
conservation of Mechanical Energy
Change in KE + Change in PE = 0 |
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Term
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Definition
P = W/t
= F x d/t
= F x v |
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Term
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Definition
Moment of inertia resists changes in angular velocity
Depends on mass and distribution of mass
Further away the mass is from the axis of rotation the more resistance to motion
ex. the bat. larger (I) when the weight was moved away from the axis of rotation. Smaller (I) when the weight is closer to the axis of rotation |
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Term
| Moment of inertia depends on _______ |
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Definition
Add up contributions of all mass elements
Radius of gyration
Known shapes
Parallel axis theorem |
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Term
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Definition
| Represents how far from the axis of rotation all the object's mass must be concentrated to create the same resistance to change in angular motion as the object had in its original shape. |
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Term
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Definition
Each axis has its own moment of inertia associated with it
More mass concentrated away from COR then it will have a higher (k)
ex. Increased inertia when moving in flexion/extension vs pronation/supination. |
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Term
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Definition
Moment of inertia at COM
Hollow disc (circle) = mr^2 - more mass is further away from COR
solid disc = (mr^2)/2 = lower (I) mass is close to COR
Rod = (mL^2)/12 |
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Term
| Parallel axis theorem (eccentric axes) |
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Definition
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Term
| Whole Body Moment of Inertia |
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Definition
Greatest moment of inertia in transverse plane
Decreases when person crouches down
Moment of inertia is greatest in sagittal plane when the arms are straight out to the side. It decreases when the arms are at the side. |
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Term
| Conservation of angular momentum 1st law |
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Definition
A rotating body will continue to turn about its axis of rotation with constant angular momentum, unless acted upon by an external torque.
H = I x angular velocity |
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Term
| 2nd law of angular analog of Newton's laws |
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Definition
The rate of change of angular momentum of a body is proportional to the torque causing it.
T = I x alpha |
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Term
| Conservation of Angular Momentum |
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Definition
When mass was closer to the COR
Reduces Moment of Inertia
Increases Angular Velocity
Momentum (H) stays constant |
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Term
Angular Kinetic Energy
To calculate muscle force for static |
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Definition
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Term
Angular Kinetic Energy
To calculate muscle force for dynamic |
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Definition
| Sum of Moment Arms = I x alpha |
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Term
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Definition
Linear Work = F x d
Angular Work = Torque x theta |
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Term
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Definition
Linear power = F x v
Angular power = T x angular velocity |
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