# HSC322_CH3

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1. the science dedicated to broad area of human movment is called:
kinesiology

• -can include sports psychology, motor learning, exercise physiology, and biomechanics
• -kinesiology is more qualitavtive, descriptive
• -describes why motions occur
2. application of principles and techniques of mehcanics to structures, functions, and capabilities of living organsims are called:
biomechanics

• -includes physics, chemistry, mathematics, physiology, and anatomy
• -more quantitative, uses calculations of variables
3. in the biomechanics of human movement decscribes, analyzes, and assesses human movement

what is the same?
what changes?
• what is the same: whether it is an elite athlete or CP, anatomy, physiology, bone structures, mechanics, and gravity force are all the same
• what changes: the task, the level of detail

once we know normal, it is easy to find abnormal
4. the study of forces and their effects are caelled:
mechanics

the application of mechanical principles to human and animals bodies in movement and at rest is called biomechanics
5. list and describe the 2 conditons/states of mechanics:
• Static: an ojbect at rest; an object with constant acceleration; constant velocity; in the body its angular motion and rotation at the same speed
• Dynamic: acceleration or decceleration; motion with acceleration
6. list and describe 2 areas of study in mehcanics:
• kinematics: characteristics of motion; variables of time, position, displacement, velocity, can be linear or angular, ROM, flexion/extension
• Kinetics: what causes motion; the reason for motion; forces, torque
7. list the 3 kinds of motions:
• Linear (translational): move from one location to another; moving in a straight line
• angular (rotary, rotation):
• general:

• -shape and fit limit movements at joints
• example: elbow - no ABD/ADD based on the design of the joint
8. Any point on the body used to measure how far the point has traveled; the ojbect/body moves as a whole is called:
Linear motion

example: a point on the heel will measure how far the heel has traveled; all parts are moving together as measure of distance in linear motion
9. the body moving as a whole in a straight line is called:
rectilinear

• - occurs with passive transport
• -example: the whole body being moved in wheelchair in a straight line
• -not much rectilinear motion occurs within the whole body motion
10. an ojbect or a point on an object moving through a curved path is called:
curvilinear

• example: throwing a bowling ball: the arm as a whole moves thru angular motion, but the wrist goes thru curvilinear motion
• -projectile motion (throwing a football), a long jump (the angle of take off), a diver (center of gravity)
• -effects of gravity-calculate speed, angle of take off
• -circulation motion- speed of gymnast on a high bar (swing)
11. movement that occur around an axis or pivot point is called:
angular motion

• -one segment (of a joint) goes thru the same arch of motion
• -every point on the segment will have the same angle, no matter which point is chosen
• -points on an object thru angular motion do not change relative to each other (no bend, or twist between points)
• -angular variables are going to be the same
12. the farther away a point is from the pivot point the [larger/smaller] the kinematic variables, while the angular variables [increase, decrease, stay the same]
the father away a point is from the pivot piont the larger the kinematic variables, while the angular variables stay the same
13. list the 3 factors that determine linear motion:
• the object is free to move (not a fixed point)
• uniform force against the side of the object
• force applied directly to COG (center of gravity)

-motion occurs unless there is a resistance or and obstacle
14. list the 3 factors that determine angular motion:
• some portion is fixed in place (vs. linear, which all portions are free to move)
• there is a fulcrum or axis of rotation
• a force is applied to the portion of the object that is free to move

-example: the muscles that ABD the hip, motion in the frontal plane, medial/lateral location of LOP, does not create flexion/extension becuase fibers run thru the center of the joint
15. the linear kinematic that describes an objects change in position is called:
Distance/Displacement

• Distance is a scalar quanitiy
• Displacement is a vector (magnitiude, dirction)
• must know inital and final coordinates
• independt of path if end points are fixed

(delta)x=xf - xi
16. the ratio of an objects displacement (delta x) and time interval (delta t) is called:
• speed/velocity
• speed is a scalar quantity
• velocity is a vector (magnitude, dirction)

Vavg= (delta)x/(delta)t
17. the ratio of the change in velocity and time interval is called:
average acceleration

aavg= (delta)v/(delta)t
18. a segment rotating around a joint goes thru:
angular motion

• -different body parts have different (linear)velocities and accelerations
• -points near the axis have displacements less than those farther awas
• -consider extened objects as large number of particles
19. describe the relationship between linear and angular motion
• Lever PA< PB<PC; linear displacement varies (see slide)
• move same angular distance in the same time

• angular variables: velocity, displacement, acceleration are the same
• linear variables: velocity, displacement acceleration, "C" has larger variables than "A" farther away from the piviot point the larger the kinematic variables
20. state the equations for angular variables:

angular displacement:
angular velocity:
angular acceleration:
• angular acceleration:
• angular velocity:
• angular displacement:
21. state the equations for linear variables of angular kinematics

displacement:
velocity:
acceleration:
• displacement:
• velocity:
• acceleration:

r= distance between points
22. the study of systems that are in a constant state of motion is called:

list 2 ways this state can be acheived:
static

• acheived
• a body/object at rest with no motion
• body/object moving at a constant velocity without acceleration

all forces acting on the body are in balance, so equilibrium
23. the study of systems in motion with accelerations is called:
dynamics

acceleration is unbalanced due to unequal forces acting on the body
24. rate of change in velocity is called:

A. acceleration
B. inertia
C. linear motion
D. angluar motion
A. acceleration
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25. motion along a line is called:

A. angular motion
B. acceleration
C. inerita
D. linear motion
D. linear motion
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26. a quality of motion that is equal to mass X velocity is called:

A. inertia
B. acceleration
C. torque
D. momentum
D. momentum
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27. motion involved in rotating around an axis is called:

A. acceleration
B. torque
C. angular motion
D. momentum
C. angular motion
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28. all of the applied forces or inertial forces acting on the moving body are in balance, resulting in movment with unchanging speed or direction is called:

a. equilibrium
b. static equilibrium
c. balance
d. dynamic equilibrium
dynamic equilibrium
29. the state of zero acceleration in which there is no change in the speed or direction of the body is called:

A. balance
B. dynamic equilibrium
C. static equilibrium
D. equilibrium
D. equilibrium
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30. a body at rest or completely motionless is called:

A. center of gravity
B. equilbrium
C. balance
D. static equilbrium
D. static dquilbrium
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31. the moment of force is called:

A. acceleration
B. torque
C. momentum
D. inertia
B. torque
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32. the ability to control equilibrium, either static or dynamic is called:

A. center of gravity
B. stability
C. linear motion
D. balance
D. balance
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33. the distance between the axis and the point of force application is called:

A. resistance arm
B. forced
C. balance
D. force arm
D. force arm
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34. mass x acceleration is:

A. linear motion
B. torque
C. inertia
D. force
D. force
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35. resistance to a change in the body's acceleration; the resistance to a change in the body's equilibrium is called:

A. balance
B. stability
C. center of gravity
D. inertia
B. stability
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36. the distance between the axis and the point of resistance application is called:

A.  force arm
B.  resistance arm
C.  balance
D. force
B. resistance arm
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37. the point at which all of the body's masses and weight are equally balanced or equally distributed in all directions is called:

A. stability
B. center of gravity
C. equilibrium
D. balance
B. center of gravity
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38. list 2 ways in which mechanical advantage can be "thought" of:
• enables us to apply a relatively small force, or effort, to move a much greater resistance
• -or-
• convert a larger amount of force to be exerted over a shorter distance
39. in the lever system the point of rotation is known as:

A. resistance
B. fulcrum
C. power
D.  force
B. fulcrum
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40. When the fulcrum is between the force and the resistance the lever system is known as a ____ class lever.

A. 1st
B. 2nd
C. 3rd
d. none of the above
A. 1st
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41. A lever system with the force between the fulcrum and the resistance is best designed for:

A. force movments
B. balanced movements
C. weak movements
D. speed and ROM
D. speed and ROM
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42. A lever system with the resistance between the force and the fulcrum is best designed for:

A. balanced movements
B. speed and ROM
C. force movements
D. weak movements
C. force movements
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43. When the resistance is between the force and the fulcrum, the lever system is known as a ____ class lever.

A. 2nd
B. 1st
C. 3rd
d. none of the above
A. 2nd
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44. How do anatomical pulleys affect:

magnitude:
direction:
.... of  a muscle force (Fms)?
• magnitude: anatomical pulleys DO NOT affect magnitiude
• direction: anatomical pulleys CHANGE the direction of the muscle force
45. how does one determine which is the..

effort arm:
resistance arm:
• effort arm: effort force is produced by the muscle;
• resistnace arm: external load; the force that resists/opposes the motion; opposes effort force
46. a child has difficulty pushing open a door into a resturant. what advice would you give them so that they could perform the task independently? why would you give that information?
• perform task independently: position his body at the edge of the door farthest away from the hinges; push perpendicular to the door
• why: force applied at a greater distance from the pivot point has a greater effect on the rotation at the hinges, perperndicular force applies a greater torque
47. describe how you would position a limb in space so taht gravity exerts the least torque on the limb:
• position the limb parallel with the pull of gravity (stright up/down)
• why: at "180" degrees or "0" degrees.. force is being applied thru the pivot point, so there will be no rotation
48. describe how you would position a limb in space to have gravity exert the greatest  torque on the limb:
• position the limb perpendicular with the pull of gravity
• why: greater lever arm distance with the pivot point
49. how do anatomical pulleys affect torque generated by the muscle that passes over the pulley?
increases the torque
50. A client is performing a unilateral, isometric tricepscurl with a 5-pound dumbbell.  The clientis laying supine with the shoulder and elbow both flexed to 90°.  The weight islocated 15 inches from the axis of rotation and the COG of the weight of theforearm and hand (4.0 pounds) is 12 inches from the elbow.  The attachment of the triceps is 0.75 inchesdistal to the elbow.  Calculate theperpendicular muscle force the triceps must produce to maintain the segment inequilibrium.
164 lbs
51. A 180 pound, 6’ 0” client is trying to maintain hisupper extremity in a position parallel to the floor (glenohumeral jointabducted to 90°).  The weightsof the upper arm, forearm, and hand are 5.0, 2.9, and 1.1 pounds,respectively.  The segment COGs arelocated 5.9”, 17.9”, and 27.9” from the axis of rotation.  Calculate the perpendicular force thedeltoids must produce to maintain equilibrium if the attachment is 2.5” fromthe axis of rotation.
44.84 lbs
52. If the distal attachment of your biceps brachiiis on your forearm 2 inches distal to your elbow, the distance from the elbowto the palm of your hand is 18 inches and you lift a 20-pound weight, how muchforce must the biceps produce to achieve elbow flexion?
180 lbs
53. If the weight of an object is 50 kg and yourmechanical advantage is 4, how much force would you need to exert to lift theobject with a lever system?
12.5 kg
54. the study of what causes motion; the reason for motion is called:
kinetics
55. an entity which produces, halts (slows down), or changes direction of motion is called:
force
56. a push or pull through contact or gravity is called:
force

• examples of push/pull contact
• object a person sits/stands on
• internally within muscles
• friction (shoes/socks, joints)
• a weight that you carry
• other people (contact sport)
• providing external forces to a patient
57. an entity that alters the motion of a body part is called:
force

• examples of forces with no motion
• static forces..
• counteraction of chair on body
• leaning against a wall
• equal and opposite forces
• isometric action
58. W=mg
weight: the pull/acceleration due to gravity
59. an external object providing a resistance; muscles that counter act the pull; amount of lifting is called:
60. the ability of an object to resist deformation; bone, skin, tendons, ligaments (at which point either bend or break) is called:
strength
61. force distributed over an area; more of a compression force, not so much a pulling forces is called:
pressure

P= force/area

MUSCLES DONT CREATE A PRESSURE; MUSCLES CREATE PULL FORCE
62. list the aspects that constitute that forces is a vector quantity:
• force has a magnitude: a muscle must apply at least the amount of force of the weight you are trying to lift
• force has a point of application:
• force has a line of application: relative to the axis
• force has a direction:

Example: for a weight lifter to lift a 250 N barbell - the lifter must apply a force greater than 250 N, in an upward direction, through the center of the gravity of the barbell
63. Open Chain Knee Extension:

Point of application:
location of line of pull:
direction of pull:
gravity's point of application:
gravity's location of the line of pull:
gravity's direction of pull:
torque of gravity:
what is the net torque:
• point of application: distal
• location of the line of pull: anterior
• direction of the pull: superior
• gravity's point of application:  distal
• gravity's location of the line of pull: anterior
• gravity's direction of pull: inferior
• torque of gravity: flexion
• what is the net torque: extension
64. example down phase of open chain knee extension:

point of application for quads:
location of line of pull of quads:
direction of the pull of the quads:
torque of the quads:
gravity's point of application:
gravity's location of the line of pull:
gravity's direction of pull:
• point of application for the quads: distal
• location of line of pull of quads: superior
• direction of the pull of quads: posterior (eccentric)
• torque of quads: extension
• gravity's point of application: distal
• gravity's location of line of pull:  anterior
• gravity's direction of pull: inferior
• torque of gravity: flexion
• net torque: flexion
65. evaluate a closed chain squat: knee flexion

point of application of quads:
location of the line of pull of quads:
direction of pull of quads:
gravity's point of application:
gravity's location of line of pull:
gravity's direction of pull:
• point of application of quads: proximal
• location of the line of pull of quads: anterior
• direction of the pull of quads: inferior
• gravity's point of application: proximal
• gravity's location of line of pull: posterior
• gravity's direction of pull: inferior
66. a body in motion tends to remain in motion at the same speed in a straight line unless acted on by a force; a body at rest tends to remain at rest unless acted on by a force is described by:
newton's 1st law

friction and air resistance effect objects in motion, friction within joints is relatively small
67. the change in acceleration of a body is directly proportional to the force causing it and inversely proportional of the mass of the body is described by:
newton's 2nd law

• a greater force is needed to move a larger mass
• the same forces acting on objects cause objects to move differently

• acceleration of a heavy vs. light object
• a=F/m
• a lighter object accelerations more (higher) than a heavy object
• the relationship between acceleration and mass is inversely proportional
68. For every action force there is an equal and opposite reaction force is described by:
newton's 3rd law

ie: muscle pulls on a bone, the bone pulls back with equal force on the tendon... otherwise the tendon tears
69. list the 2 different types of pulley systems:
• linear: cables/forces are parallel or perpendicular
• concurrent: cables/force applied at different angles

the body is a FIXED LINEAR system
70. describe the characteristics of pulley:
• frequently used in exercise and traction
• fixed or movable positions (found within the body)
• change direction of the force (fxn of any system)
71. what is changed in a single fixed pulley system:
• the lind of action of force is changed
• there is NO CHANGE in magnitude
72. what is the mechanical advantage to the force in a single fixed pulley system:
there is NO mechanical advantage to the force, there is ONLY CHANGES in DIRECTION
73. what kind of pulley system is found in the body:
single fixed pulley sytsem
74. how do bony prominences or soft tissues affect anatomcial pulleys:
• deflects tendons from a straight course (causes the change of direction)
• changes the angle of pull of muscles providing the force (perpendicular/parallel components)
• an increase in the angle of pull increase the rotary component (the perpendicular component)
75. compare the pulley system of a the knee without the patella to the system with the patella
• pulley system without the patella
• smaller moment arm
• the distance from the pivot point to the action of the force is small
• smaller perpendicular component
• 50% decrease in torque production w/o patella
• contracts with same force as with a patella

• pulley system with a patella
• a larger moment arm
• a larger distance from the pivot point ot hte action of the force
• the perpendicular component is larger; more torque produced
76. a rigid bar that can rotate about a fixed point when a force is applied to overcome a resistance is called:
a lever
77. what are the two goals of levers:
• to overcome a resistance larger than the magnitude of the effort applie (lift weight with a lower value of force)
• increase the speed and ROM throught we a resistance can be moved

inverse relationship: both goals can be acheived in one task
78. define:

force arm:
resistance arm:

relate the following to the anatomical lever:
the bar:
the pivot/axis:
the effort force:
the weight force:
• force arm: the point of application of the force to the pivot/axis
• the resistance arm: the distance from the weight to the pivot point

• the bar: the bone
• the pivot/axis: the joint
• the effort force: the muscle
• the weight force: the weight of the object or segment being lifted
79. the ratio between length of the force arm and the length of the resistance arm is called:

• MA= FA/RA
• MA= W/F

the higher the #, the greater the mechanical advantage (force advantage)

MA is unit-less
80. 1st class levers

central component:
list the 3 fxnal desings in relationship to the axis:

examples in the body:
central component: axis

• fxnal designs relation to axis
• balanced movments: the axis is near the middle; example seesaw
• speed and ROM movements: the axis is near the force; example scissors
• force motion: the axis is near the resistance; example crowbar

• examples in the body
• skull and C1
• the solecus muscle and the ankle
81. 2nd class levers

central component:
MA:
fxnal design in relationship to the axis:
• central component: weight/resistance
• MA: will always be bigger than 1
• type of advantage: force ( apply less force; and move more weight)
• fxnal design in relation to axis: force motions (a large resistance can be moved with relatively small force); the axis is near the resistance
• example: wheelbarrow
82. 2nd class levers:

moving the resistance closer to the axis ________ the mechanical axis, and _____ the distance the resistance is moved.

the closer the resistance is positioned to the force the ______ the mechanical advantage, but _______ the distance the resistance is moved:
moving the resistance closer to the axis increases the mechanical axis, and decreases the distance the resistance is moved.

the closer the resistance is positioned to the force the less the mechanical advantage, but greater the distance the resistance is moved:
83. 3rd class levers:

central component:
MA:
fxnal design in relationship to the axis:
• central component: force
• MA: always less than 1
• type of advantage: distance ( a greater distance over which force is applied, provides for greater velocity)
• fxnal design in relation to axis: speed and ROM; axis is near the force

this type of lever is the most found in the body
84. 3rd class levers:

moving the point of force closer to the axis _____ the speed and ROM, and requires _____ force.

moving the force closer to the resistance _____ the force needed, and ______ the speed and ROM.
moving the point of force closer to the axis increases the speed and ROM, and requires greater force.

moving the force closer to the resistance decreases the force needed, and decreases the speed and ROM.
85. the tendency of a force to rotate a body about an axis (moment of force) is called:
torque

• -when a force is properly exerted on a rigid body pivoted about some axis, the body will tend to rotate about that axis
• -force is applied away from the pivot at the segment free to move
86. state the 2 equations for torque
•   where....
• r=distance from the pivot to point where force is applied
• F=magnitude of the force
• sin f= angle of where force is at in relation to teh segment we are trying to move

• d=r sin f   where....
• d= moment arm (lever arm)
87. the perpendicular distance from the axis to the line of action of force is called:
the moment arm
88. the torque of an external force chanages as_____
the torque of a external force changes as we go thru ROM

• -as we change position, torque changes
• -when a force is perpendicular to teh "arm" it produces the greatest amount of torque
89. in regards to torque on rotating segments, muscles that exert torque are dependent on what 4 things:
• point of insertion of the the muscles: closer to teh attachment, the smaller the lever arm; the farther from the attachement the longer the lever arm
• length: optimal force @ slightly stretched
• tension:
• angle of pull: affects the rotary component for the force; if the angle of pull is at 90, all the force goes to rotation
90. the biceps produce 120 lbs force, 1 inch from the elbow. the weight of the forearm and hand is 10 lbs, COG is 10 inches from the elbow. a weighted ball is 5 lbs and is 15 inches from the elbow.  what net torque occurs at the elbow
• T = 0
• Tflexion=Textension
• Fr=Fr + Fr
• 120(1)=10(10)+5(15)
• 120= 100+75
• 120lbsflexion=175lbsextension
• Net torque: Extension
91. the biceps are 1 inch from the elbow. the weight of the forearm and hand is 10 lbs, COG is 10 inches from the elbow. a weighted ball is 5 lbs and is 15 inches from the elbow.  what net torque occurs at the elbow...how much force do the biceps have to create to keep the system in equilibrium?
• T=0
• Tflexion=Textension
• F(1)=10(10)+5(15)
• F=100+75/1
• F=175lbs
92. list 4 ways to define the center of gravity:
• point of application of force due to gravity
• point where weight/mass is concentrated at
• "balance point"
• point where all forces appear to act
93. the line of application for gravity force is called:

line between COG of object and:
direction:
point of application:
• line of gravity (LOG)
• line between COG of object and:
• direction: inferior
• point of application: to the center of the earth
94. describe the 3 characteristics of center of gravity in humans:

COG in females:
COG in males:
• COG in the body is the sum of segments COG
• Combination of segments
• location of COG of a human in normal standing position varies with body build, age, sex
• Females: ~55% of standing height
• males: ~57% of standing height
95. describe the combination of a segments COG:

ie: the biceps, elbow, forearm, hand:
• COG is a straight line between two segments
• COG is slightly toward the heavier segment
• COG can be outside of the body.. many times it IS outside the body
96. what is a common feature of the location of the COG of a segment:
• all of the segments have about the same location of COG
• COG is more proxmially located on a segment
• *the proximal part of the segment tends to be thicker, where the distal part of the segment tends to be thinner
97. what is the benefit of understanding/knowledge of the center of gravity:
• helps to elminate the possibility of falls
• alters exercise loads: an object of weight becomes part of the system
• helps faciliatate motion: stability; mobility-loss of stablilty..puts the COG outside of the body
• balance segments
98. generally where is the COG located:
• S2
• from a transverse view: slightly posterior
99. When a segment changes position, so does the COG, describe movements that will:

raise COG:
drop COG:
• Raise COG: raise the arms, stand on toes, put external weight on shoulders
• drop COG:
100. Describe the qualities of COG and walking:
• High COG
• unstable equilibrium
• Small forces can cause displacement of the body
• Sequence of disturbing and catching COG

• #1 ... Lean forward, move COG toward toes
• #2 .... Not fall... Take step... COG is between stride
101. A person _______ COG for protection.
• a person lowers their COG for pprotection at require more energy- may cause further loss of balance
• Example novice skiers: the try to almost "sit down" to move COG backwards to creat stability; when they lean foward they increase speed
102. objects at rest:
forces are balanced:
• Objects at rest: equilibrium
• forces are balanced

• the sum of the forces = 0, No acceleration
• the sum of torque=0, No rotation

objects at rest are not all equally stable ; there are "levels" of stability
103. If a baseball player hit a triple and ran around the bases to third base, what would be his displacement? (Hint: The distance from each base to the next is 90 feet.)

A. 0 feet
B. 90 feet
C. 270 feet
d. none of the above
B. 90 feet
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104. Object A has four times greater mass than Object B. If both have the same acceleration, the force applied to Object A will be how large or small as compared to the force on Object B?

A. two times
B. one-fourth
C. four times
D. one-half
C. four times
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105. Two points (A & B) are located on a rotating rigid body segment. Which of the following kinematic variables of point A & B will be the same, regardless of which point is further from the pivot?

a. angular kinematics
b. linear kinematics
a. angular kinematics
106. The perpendicular component of a force causes which of the following?

A. rotation
B. distraction
C. linear motion
D. compression
A. rotation
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107. If a lever system has a mechanical advantage greater than 1, what type of advantage does the lever have?

(this multiple choice question has been scrambled)
108. A force advantage means which of the following:

a. A weight can be moved through a larger arc of motion with faster speed.
b. a weight can be moved with lesser force
c. none of the above
b. a weight can be moved with lesser force
109. If the mechanical advantage of a lever is 10 and the resistance is 100 pounds, what is the force?

A. 10 lbs
B. 1000 lbs
C. none of these answers
D. 100 lbs
A. 10 lbs
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110. A distance advantage means which of the following?

a. A weight can be moved through a larger arc of motion with faster speed
b. a weight can be moved with lesser force
c. none of the above
a. a weight can be moved throught a larger arc of motion with faster speed
111. As your client is doing a squat, gravity causes hip flexion to occur during the downward motion of the body. What torque do the hamstrings and gluteus maximus produce at the hips?

A. none
B. flexion
C. extension
C. extension
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112. 1 If an object is in unstable equilibrium and a force is applied to the object such that the COG is disturbed, what will happen?

A. the COG returns to its inital position
B. the COG finds a new position
C. nothing
D. the 1 If an object is in unstable equilibrium and a force is applied to the object such that the COG is disturbed, what will happen?
B. the COG finds a new position
(this multiple choice question has been scrambled)
113. when a force is applied there is a slight distrubance, and when the force is removed the object's COG returns to the initial position:
stable equilibrium

• examples:
• blocking dummie at FB
• webbles wobble but they dont fall down
• sitting on a chair, a slight push will rock the chair, but returns back to position
114. why does the object come back to its initial position in stable equilbrium?
• the center of gravity is lower
• bottom heavy casuse COG to be low
115. when a force is applied the COG of the object is disturbed, and the object finds a new position:
unstable equilibrium
116. a force applied to an object in which the COG does not fall or return to its inital position is called:
neutral equilibrium
117. focusing on stable/unstable equilibrium list the factors that affect stability:
• the height of the COG: higher COG object is less stable; lower COG of object is more stable
• size and shape of the base: wider base is more stable
• location of LOG within the base of support:
• weight or mass of the body: consider the COG..a weighted vest may increase the height of COG
118. in regards to the size of the base of support, what two qualities make the COG stable:
• a large BOS is more stable
• the more centered the COG is within the BOS, the more stable

the COG in BOS; equilibrium
119. what shape of BOS would resist anterior-posterior forces:
what shape of BOS would resist lateral forces:
• resist AP forces: a staggered one in front, one behind stance
• resist lateral forces: a stance that hip width apart
120. in a dynamic situation, standing on a moving bus, and then the bus is goin to stop...how do you keep your balance:
• postion the shape of the BOS with the direction of the force
• lean, move the COG to one limb, this allows the COG more time to travel before the force (before we fall)

dynamic situations need greater distance to travle for the COG
121. what are the benefits of the shape of the BOS:
• allows for the COG to move
• change the shape of BOS in relation to the kind of force we are expecting
122. the location of the line of gravity is in equilibrium when:
the line of gravity is within the BOS
123. how does the mass of a body affect stability:
• mass of the body is only a factor when motion or an external force is involved
• the greater the mass, the greater the stability
 Author: itzlinds ID: 240596 Card Set: HSC322_CH3 Updated: 2013-10-30 14:25:08 Tags: Kinesiology kinematics Folders: Description: Kinesiolgy Show Answers: