Flashcards in Chapter 7 - Biomechanics Deck (99)
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31
give an example of a first class lever
teeter-totter
32
give an example of a second class lever
wheelbarrow
33
give an example of a third class lever
barbaque tongs
34
factors affecting the moment of force
a balanced teeter-totter
35
newtons 1st law of motion
the law of inertia
36
the law of inertia
a body will maintain a state of rest or constant velocity unless acted on by an external force that changes the state
37
newtons 2nd law of motion
the law of acceleration
38
the law of acceleration
a force applied to a body causes an acceleration of that body of a magnitude proportional to the force, in the direction of the force, and inversely proportional to the body's mass
39
newtons 3rd law of motion
the law of reaction
40
the law of reaction
- for every action there is an equal and opposite reaction
- the 2 acting forces are equal in magnitude, but opposite in direction
41
give an example of the law of reaction (newtons 3rd law of motion)
the sprinter exerts a force on to the blocks and simultaneously the blocks exert an equal force back onto the sprinter
42
what is the action and what is the reaction in this example of newtons 3rd law?: the tires on a car push on the road and the road pushes on the tires
action: the tires on a car push on the road
reaction: the road pushes on the tires
43
what is the action and what is the reaction in this example of newtons 3rd law?: while swimming, you push the water backwards and the water pushes you forward
action: while swimming you push the water backwards
reaction: the water pushes you forward
44
what is the action and what is the reaction in this example of newtons 3rd law?: a rocket pushes out exhaust and the exhaust pushes the rocket forward
action: a rocket pushes out exhaust
Reaction: the exhaust pushes the rocket forward
45
why are the models of human motion developed?
because the total movement capacity of all the body structures is to complex to accurately analyze
46
why is the total movement capacity of all the body structures too complex to accurately analyze? (3 reasons)
1) anatomical difference in people related to race, age, gender, health and lifestyle
2) the body is susceptible to deformation and multi-segmental so that one segment affects the others during movement
3) sport skills occur in 3D often encountering all 3 planes and axis
47
what are the 3 human body models?
1) particle model
2) stick figure model
3) rigid segment model
48
particle model
used when the object of interest (the human body or an object) is airborne after being thrown, struck or kicked the body itself (i.e., jumping, diving, tumbling)
49
stick figure model
used when the object is in contact with its environment and generally gross motor skills in 2D (i.e., sprint starts, running, non rotational dive)
50
rigid segment model
used for more sophisticated quantitative analyses (3D) especially in multi-plane motions
51
what 2 things are required for rigid segment model?
camera and 3D analysis
52
what is the first preliminary step for analyzing human motion?
identify the system to be studied, which is to separate the object of interest from its surroundings
53
what is the second preliminary step for analyzing human motion?
identify the frame of reference in which the movement takes place
54
what is the third preliminary step for analyzing human motion?
identify the type of motion that is occurring, the body planes in which movement takes place (sagittal, frontal or transverse and
identify the axes of rotation about which rotational motion occurs (sagittal, frontal, or vertical)
55
what are the 3 types o motion?
linear, general and angular
56
motion
when all parts of the body move the same distance in the same direction at the same time
57
linear motion (AKA translation)
refers to movement of the body as a unit without individual segment parts of the body moving relative to one another
58
rectilinear motion
occurs when movement follows a straight line
59
curvilinear motion
occurs when the movement path is curved
60
