L13

Question 1

Angular motion occurrs when:

Answer 1

All parts of a body move through the same angle but do not undergo the same linear displacement

Question 2

Angular kinematic describes

Answer 2

Angular motion without regard to the causes of the motion

Question 3

Most human motion is a result of

Answer 3

Angular motion of the limbs that occur around joints

Question 4

Degree: one circle/ one complete rotation

Answer 4

360 degrees

Question 5

Revolution/ Number of rotations per one circle

Answer 5

One revelution

Question 6

Radian: one circle= 2 pi radians

Answer 6

1 rad= 57.3 degrees

Question 7

How to convert degrees to radians: ex 50 degrees

Answer 7

50 degrees/ x = 360 degrees/ 2 pi rad
-divide the degrees by x, equal it to 360 divided by 2 pir, then cross multiply to get 2pirad x 50 =360(x), solve for x by dividing 50 x 2pi radians by 360

Question 8

How to convert radians to revolutions: ex 10 radians

Answer 8

10 rad/ x = 2 pi radians/ 1
-cross multiply to get 2 pi rad x (x) =1 (10 rad), so divide 1 (10rad) by 2 pi radians

Question 9

How to convert revolutions to degrees: ex 3.3 revolutions

Answer 9

3.3rev/ x = 1rev/ 360 degrees
-cross multiply to get (3.3)(360) = 1(x), then divide by 1 to isolate x

Question 10

Angular position

Answer 10

Orientation of a line with another line or plane

Question 11

Absolute angular position (angle)

Answer 11

Angle of a single body segment with respect to a known vertical or horizontal
Ex) angle of the trunk is calculated with respect to the vertical plane

Question 12

Relative Angular Position (angle)

Answer 12

-angle of one refment relative to another
-angle between longitudinal axes of 2 segments
Ex) angle of the trunk is calculated with respect to the knee, hip, and torso

Question 13

Absolute segment angles

Answer 13

Calculated using tan
Tan: the ratio of the side opposite the angle and the size adjacent to the angle
TOA

Question 14

Absolute Segment values calculated using

Answer 14

Tan= TOA
(Yproximal- Ydistal) / (Xproximal- X distal)

Question 15

Relative angles use:

Answer 15

Law of Cosine
-relationship between the side of a triangle that doesn’t contain a right angle
CAH
-adjacent/ hypotenuse

Question 16

Relative angles: law of Cosines uses:

Answer 16

Pythagoreans theorem
A= square root of (Xprox- X dist) squared + (Yprox- Ydist) squared
-need to use for all 3 side lengths of a triangle

Then: find cos for angle of triangle

Question 17

Axis of rotation

Answer 17

-fixed line about which a rigid body rotates
-always perpendicular to its plane

Question 18

Axis of Rotation

Answer 18

-direction of a rotation of angular motion referred to as the polarity of the vector

Question 19

Right Hand Rule

Answer 19

-fingers curl the same direction as the rotation of the limb trying to determine the rotation of
-if thumb is pointing right or up, it is positive
-if thumb is left or down, it is negative

Question 20

Angular distance is

Answer 20

The sumn of all angular changes (scalar)

Question 21

Angular Displacement is:

Answer 21

The difference between the final and initial positions (vector)

Question 22

Angular Displacement calculated by:

Answer 22

Change in angle= angle final- angle initial
Ex) 170 degrees- 5 degrees
Final change in angle= 165 degrees

Question 23

Linear displacement of a point on a rotating object or rigid body is directly proportional to

Answer 23

The distance that point is from the axis of rotation
-the greater the radius, the greater the linear displacement

Question 24

Linear Displacement

Answer 24

L= change in angle x radius
L= length of arc
Change in angle= angle measured in radians
R= radius

Question 25

The larger the radius of rotation (r),

Answer 25

The greater the linear distance travelled by a point of a rotating object or rigid body

Question 26

Angular speed

Answer 26

The angular distance travelled per unit of time as a scalar quantity

Question 27

Angular velocity

Answer 27

Omega (w) -vector quantity that describes the time rate of change of angular position (in rad/s or degrees/ s) W= change in angle/ change in time (Final angle- initial angle)/ change in time

Question 28

Average Angular Velocity

Answer 28

Calculated anglular velocity for the object or rigid body through a certain angular displacement

Question 29

Instantaneous Angular Velocity

Answer 29

Calculated angular velocity at a specific instant when an object or rigid body is rotating

Question 30

Angular Acceleration

Answer 30

Alpha (weird a) -rate of change in angular velocity measured inn radians per second squared or in degrees per second squared Alpha= change in angular velocity/ change in time (Final angular velocity- initial angular velocity) / change in time