chapter three

Question 1

composite approach

Answer 1

qualitative analysis approach that views the whole body as a system that progresses through stages or phases as it refines movement patterns

Question 2

component approach

Answer 2

qualitative analysis approach that views the body in component sections, with each section progressing through more refined steps toward mature movement patterns

Question 3

scalar quantity

Answer 3

a quantity that can be fully specified simply with a single numerical magnitude of appropriate units

Question 4

mass (m)

Answer 4

the quantity of matter of which a body is composed

Question 5

inertia

Answer 5

a body’s resistance to having its state of motion changed by application of a force

Question 6

vector quantity

Answer 6

a quantity that can only be fully specified with a magnitude of appropriate units and a precise direction

Question 7

weight

Answer 7

measure of the force with which gravity pulls on an object’s mass

Question 8

direction

Answer 8

sense or way in which a force is applied; represented by the tip of a vector

Question 9

orientation

Answer 9

the alignment or inclination of the vector in relation to the cardinal directions

Question 10

point of application

Answer 10

the point or location at which a system receives an applied force; usually defined by the tail of the vector

Question 11

magnitude

Answer 11

size or amount of an applied force; represented by the length of a vector

Question 12

line of action

Answer 12

an imaginary line extending infinitely along a vector through both the tip and tail, representing the path along which the vector would travel if moved forward or backward

Question 13

polar coordinate system

Answer 13

a coordinate system in which the location of the given point is defined by its distance (radius) r from the origin and by the angle between the chosen reference axis and the line formed by connecting the given point to the origin

Question 14

plane polar coordinates

Answer 14

coordinates representing the location of a point within a polar coordinate system

Question 15

pythagorean theorem

Answer 15

an expression of the relationships (ratios) between the lengths of the sides of a right triangle: r = square root of x^2 + y^2

Question 16

vector equality

Answer 16

property that two vectors are considered equal (A=B) as long as they possess the same magnitude and orientation

Question 17

commutative law of addition

Answer 17

the sum of vectors added together is independent of the order of addition: A + B = B + A

Question 18

associative law of addition

Answer 18

the sum of three or more vectors is independent of the grouping of the vectors for addition: (A + B) + C = A + (B + C)

Question 19

negative of a vector

Answer 19

another vector that, when added to the first, gives a sum equal to zero

Question 20

resultant

Answer 20

a single vector representative of the sum of multiple vectors

Question 21

vector resolution

Answer 21

the process by which individual directional component vectors of a single vector are determined

Question 22

component vectors

Answer 22

the individual vectors that are representative of each of the multiple effects that one vector represents

Question 23

vector chain

Answer 23

a form of vector analysis in which vectors are arranged tip to tail

Question 24

vector composition

Answer 24

process by which two or more vectors are summed to determine a single resultant vector

Question 25

colinear vectors

Answer 25

vectors that have the same line of action

Question 26

rotary component

Answer 26

the vertical or perpendicular component of a muscle force vector representing the amount of force that would tend to cause joint rotation

Question 27

stabilizing component

Answer 27

the horizontal (parallel) component of a muscle force vector directed toward the joint, representing the amount of force that would tend to stabilize the joint

Question 28

destabilizing component

Answer 28

the horizontal (parallel) component of a muscle force vector directed away from the joint, representing the amount of force that would tend to destabilize the joint

Question 29

Q angle

Answer 29

the quadriceps angle formed by the longitudinal axes of the femur and tibia, which approximates the resultant line of action of the quadriceps muscles

Question 30

line of pull

Answer 30

resultant line of action of a muscle force vector

Question 31

teaching cues

Answer 31

single words or short phrases that identify critical elements of a skill