Term
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Definition
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Term
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Definition
deals with the time, space, and mass aspects of a moving systme. Can be divided into osteokinematics and arthrokinematics.
page 71 |
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| What are force and vector? |
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Definition
Force is a push or pull action
Vector has both magnitude and direction
velocity is a vector |
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Definition
| two or more forces acting along the same line |
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Definition
force occurs in the same plane and in the same or opposite direction. page 73
a seesaw is an example of parallel force
a back brace like in fig 7-4 is a different type of example |
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Definition
| two or more forces must act from a common point but pull in differnt directions 7-2 and 7-6 pages 73 and 75 |
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Definition
| two forces act in an equal but opposite direction resulting in a turning effect. 7-9 page 75 |
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Term
| resultant force or parallelogram method |
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Definition
| resultant forces of unequal forces moves toward the stronger force |
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Term
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Definition
Moment of force. ability of a force to produce rotation about an axis. The amount of torque a lever has depends on the amount of force and the distance it is from the axis.
Torque is the tendency of a force to cause rotation about an axis |
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| Newtons first law is the Law of inertia |
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Definition
an object at rest tends to remain at rest and object in motion remains in motion.
a force is needed to overcome inertia and cause the object to stop move or change direction |
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| Newtons second law is the Law of acceleration |
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Definition
| the amount of acceleration depends upon the strength of the force applied to the object |
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Term
Explain Newton's third Law.
the law of action reaction |
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Definition
| for every action there is an equal and opposite reaction |
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Term
Torque in the body
moment arm or torque is |
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Definition
the perpendicular distance between the muscles line of pull and the center of the joint which is the axis of rotation
Torque can be increased by increasing the force applied
or
increasing the length of the handle ie force arm |
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Term
torque in the body
torque is greatest when.... |
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Definition
| the angle of pull is at 90° |
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Term
| muscle direction is not always the line of pull. T or F |
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Definition
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Term
| an object is in a state of equlibrium when..... |
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Definition
| all torques acting on it are even. it is then balanced |
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Term
| the security or precariousness of an objects equlibrium is depends upon the relationship between..... |
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Definition
the COG and BOS
center of gravity
base of support |
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Term
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Definition
the point of an object at which torque on all sides is equal
also
where the cardinal planes of the body intersect
or
anterior to s2 |
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Term
| to be stable an objects line of gravity LOG and Center of gravity COG must remain within the |
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Definition
BOS base of support the wider the BOS the more stable the object
since the LOG passes through the COG you could say the COG must remain within the BOS to be stable |
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Term
| How to increase stability? |
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Definition
1 Widen BOS
2 increase Mass - greater mass greater stability
3 increase friction between BOS and the supporting surface
4 watch a stationary object when moving |
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Term
Levers
Remember ARF
First class lever A in middle FAR
second class lever R in middle ARF
third class lever F in middle AFR
A= axis
F = Force
R = Resistance give examples of each lever type |
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Definition
Seesaw first class lever
Wheelbarrow second class lever
door hinge exp page 82 |
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Term
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Definition
Mechanical advantage = Force arm / Resistance arm
ratio |
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Term
| what are the four simple machines that can change the magnitude of direction and force? |
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Definition
Lever
Pulley
Wheel and axle
inclined plane |
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Term
| Stabilizing force vs dislocating force. |
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Definition
Think of close packed or loose packed joints. If a joint is in close packed position it is stable
in loose packed position the joint is further apart ie dislocated. Not like in the injury just further apart. |
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Term
| The first class lever FAR has the mechanical advantage of ___ |
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Definition
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Term
| The second class lever ARF has the mechanical advantage of ______ |
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Definition
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Term
| The third class lever AFR has the mechanical advantage of _____ |
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Definition
Range of Motion sometimes called speed and distance
many examples in the human body |
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Term
| Brachioradialis is used as an example of what type of lever? |
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Definition
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Term
| What would it take to change the class of lever of the brachioradialis from second class to third class. |
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Definition
Place weight in the hand. This moves the resistance from between the Axis and the force to further from the axis than the force.
resistance is forearm ARF <-> AFR resistance is wt in hand
page 84 fig 7-30 |
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Term
| The direction of movement in relation to gravity can change the lever class. Give an example |
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Definition
Biceps contracting eccentrically
page83 bottom and page 84
when the biceps is contracting eccentricaly gravity becomes the force and the biceps becomes the resistance |
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Term
| If MA = 1 what does this mean? |
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Definition
| FA = RA the system is balanced and is a first class lever |
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Term
| If MA < 1 what does this mean? |
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Definition
Third class lever
FA is less than the RA less torque less power
remember the advantage of third class lever is ROM |
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Term
| If MA > 1 what does it mean? |
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Definition
FA is greater than the RA more torque more power
Second class lever has the advantage of |
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Term
True or False
What is true of simple machines is that what is gained in force is lost in distance and vice versa. |
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Definition
T
in regards to simple machines, less force is needed to cause motion when the mechanical advantage is greater |
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Term
| A fixed pulley is a simple machine. It is used to ____ |
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Definition
| Change the direction of force. It is a first class level |
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Term
| There are fixed pulleys and moveable pulleys. Fixed pulleys can change the direction of force. What can moveable pulleys do? |
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Definition
| Change the magnitude of force. |
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Term
MA of a wheel is calculated as
MA = radius of wheel/ radius of axle |
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Definition
MA = 1 think of a faucet with the handle removed it is difficult to turn on a faucet by turning the axis.
MA > 1 there is a handle (wheel) on the axis. The longer the handle the greater MA, but it must be turned a longer distance. |
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Term
| Are there any examples in the human body of an inclined plane? |
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Definition
| No The longer the inclined plane the longer the distance that must be travelled, but amount of effort is decreased. Shortening the distance of the ramp increases the slant and the effort to ascend it. |
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Term
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Definition
| Scalar quantity describes only magnitude |
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Term
| Less force is required if ou put the resistance as close to the _____ as possible and apply the force as far from the ____ as possible. |
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Definition
| Less force is required if ou put the resistance as close to the axis as possible and apply the force as far from the axis as possible. |
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Term
| The larger the _______ is in relation to the axle the easier it is to turn. |
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Definition
| The larger the wheel is in relation to the axle the easier it is to turn. |
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Term
T or F
Forces can be stabilizing, Angular or dislocating.
inclined planes exchange increased distance for decreased effort
Fixed pully's change the direction of force. |
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Definition
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