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10- - Coggle Diagram

- - - - in the anatomical position,the
        COG lies approx anterior to the 2nd sacral vertebra
        -but as humans do not remain fixed in this position,
        the precise location of the COG changes constantly
        with every new position of the body n limbs
        -the bodily proportions of the individual also effect the location of COG
- - - - body is at rest or completely motionless
    - - all applied & inertial forces acting on the
        moving body are in balance
        -resulting in movement with unchanged
        speed or direction
- - - - fulcrum is positioned between the force & resistance
        
        gain either force or distance
        depending on the lengths of force & resistance arms.
        -if 2 forces are equal on either side of a 1st class lever,
        the force with the longer arm has the advantage.
        
        the side frm the axis that has the advantage is the one with the greater product of the larger force & the longer arm length.
        
        if both have equal forces with equal lever arm lengths or an equal product of force & lever arm length,
        then the system is in equilibrium
        -here mechanical advantage will be 1
        ie the same amnt of effort is
        required to move an equal amnt of resistance.
        
        eg: see-saw
        in HB: few examples
        atlanto-occipital joint
      - fulcrum/axis is central
    - - resistance is between fulcrum & effort so that the lever arm of the resistance is always shorter than the lever arm of the force.
        
        so provide a force advantage so large weights can be supported or moved by a smaller force
        
        mechanical adv >1
        -allows large force generation
        -a force advantage
        
        eg: wheel barrow
        in HB: not many 2nd cl levers in the body
        a person standing on the balls of his feet
        
        triceps surae
        
        rear molars of the jaw
        
        the body rarely has a mechanical advantage
        over the resistance forces it encounters
      - resistance/load is central
    - - force betw the resistance & fulcrum so that the resistance arm is always longer than force arm
        so the mechanical advantage lies with resistance force
        
        this arrangement is designed to produce speed of the distal segment & move a small weight a long distance
        -thus in the human body, a small amnt of shortening of a muscle(eg:brachialis) causes a large arc of motion at the joint(eg:elbow) to position the end segment(the hand)in a large range of positions
        
        this type of lever occurs in most open-chain motions of the extremities
        
        most common arrangement in the body
        
        allows great movement
        
        mechanical adv <1
        -a force disadvantage
        -is for speed
        
        eg:
        in HB: is most common in HB
        in most open-chain motions
        the biceps & brachialis flexing the elbow
        to bring a cup to mouth.
      - * force is central
    - - mechanical advantage = force arm length/resistance arm length
        (ratio betw these two)