3.1 Biomechanics Flashcards

1
Q

What is netowns first law of motion?

A

Inertia – states that an object will remain at rest or in uniform motion in a straight line unless acted upon by an external force. It is the reluctance of a body to change its state of motion

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2
Q

What is newtons second law of motion?

A
  • Acceleration of a body is proportional to the force causing it and the acceleration takes place in the direction in which the force acts
  • F=ma
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3
Q

What is scaler motion?

A

no direction but movement

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4
Q

What is vector motion?

A

direction and movement

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5
Q

What is newtons third law of motion?

A
  • When one object exerts a force on a second object, there is an equal and opposite force exerted by the second object on the first
  • For every action there is an equal and opposite action
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6
Q

What are all the vertical forces?

A
  • gravity

- reaction force

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7
Q

What is reaction force?

A

where the points of contact are

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8
Q

Where is gravity acting from?

A

center of mass

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9
Q

What are the horizontal forces

A

air resistance

friction

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10
Q

WHere does friction act from

A

point of contact

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11
Q

Where does air resistance acto from?

A

center of mass to behind you

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12
Q

What is linear motion?

A

straight line

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13
Q

What is angular motion?

A

rotation about a particular point (axis of rotation)

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14
Q

What is general motion?

A

rotation and straight line motion

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15
Q

What is velocity?

A

rate of change in displacement

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16
Q

WHat is the velocity equation?

A

displacement / time taken

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17
Q

What is momentum?

A

quantity of motion possessed by a moving body

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18
Q

What is momentum equation?

A

mass x velocity

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19
Q

What is acceleration?

A

rate of change in velocity a

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20
Q

acceleration equation?

A

(final velocity - initial velocity) / time taken

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21
Q

What is force

A

push or pull that alters the state of motion of a body

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22
Q

How do you calculate force?

A

mass x acceleration

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23
Q

What is net force (resultant force) ?

A

the sum of all forces acting on the body

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24
Q

What is reaction?

A

the equal and opposite force exerted by a body in responce to the action force placed upon it

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25
Q

Force causes a moving body to?

A
  • change direction
  • Accelerate
  • Decelerate
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26
Q

What is the centre or mass?

A

the point at which the body is balanced in all directions, or where all the mass could be considered to be concentrated

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27
Q

What is the center or mass continuously doing?

A

changing

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28
Q

What is stability?

A

the ability of a body to resist motion and remain at rest

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29
Q

What are the factors effecting stability?

A
  • mass of the body
  • height of the center or mass
  • base of support
  • line of gravity
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30
Q

How is the fosbury flop beneficial?

A
  • uses j curve to allow greater velocity
  • plants outside leg to allow inside leg to lift, along with arms, at take off to raise the center of mass as high as possible
  • fully extends spine to rotate around the bar moving the center of mass outside of the body and below the bar. Only one section of body has to be above the bar at one time.

( center of mass passes underneath the bar, fosbury flop requires less take off force to clear the same height as earlier techniques . when maximum force is generated at take-off greater heights can be achieved.)

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31
Q

How does mass effect stability?

A

greater mass, greater inertia , greater stability

32
Q

How does height of center or mass effect stability?

A

lower center of mass, greater stability

33
Q

How does base of support effect stability?

A

greater size of the base, greater stability

34
Q

How does the line of gravity effect stability?

A

more central line of gravity to the base of support, greater stability

35
Q

What are lever systems?

A

co-ordination of our bones and muscles, primarily to create human movement

36
Q

Two main functions of lever systems?

A
  • to generate muscular effort to overcome a given load

- to increase the speed of a given movement

37
Q

What are the 4 component parts of a lever system?

A
  • lever
  • fulcram
  • effort
  • load
38
Q

Give example of a lever?

A

bone

39
Q

Give example of a fulcram?

A

joint

40
Q

Explain first class lever?

A

effort … fulcrum ….. load

41
Q

Example of first class lever?

A

extension of neck when preparing to head a football

42
Q

Explain a second class lever?

A

effort … load … fulcrum

43
Q

Examples of second class lever ?

A

ball of the foot in take off phase of high jump

44
Q

Explian third class lever?

A
  • fulcrum … effort … load
45
Q

Example of third class lever?

A

flexion of elbow during bicep curl

46
Q

What is the distance from the fulcrum to the effort known as ?

A

effort arm

47
Q

WHat is the distance from the load to the fulcrum known as ?

A

load arm

48
Q

the greater the distance of the effort or load from the fulcrum …

A

more significant the effort or load becomes

49
Q

What is a mechanical advantage?

A

second class lever systems where the effort arm is greater than the load arm. a large load can be moved with a relatively small effort

50
Q

WHat is a mechanical disadvantage?

A

third class lever systems where the load arm is greater than the effort arm. a large effort is required to move a relatively small load

51
Q

What does a distance time graph show?

A

the distance a body travels over a given time

52
Q

What does the gradiant show in a distance time graph?

A

speed of the body

53
Q

How do you work out distance travelled on a speed/time graph?

A

area under the graph

54
Q

What is angular motion?

A

movement of a body or part of a body in a circular path about an axis of rotation

55
Q

What does angular motion result from?

A

eccentric force being applied to the body

56
Q

What is a torque?

A

measure of turning force applied to the body

57
Q

Sporting example of angular motion?

A

gymnastics sommersault

58
Q

What is a principal axis of rotation?

A

an imaginary line that passes through the center of mass about which the body roatates

59
Q

What are the three axis of rotation?

A
  • longitudinal
  • transverse
  • frontal
60
Q

What is the longitudinal axis?

A

-runs from head to toe through the center of mass

61
Q

What is the transverse axis?

A

from left to right through the center of mass (somersaults)

62
Q

What is the frontal axis?

A

runs from back to front through center of mass (cartwheel)

63
Q

What is angular velocity?

A

rate of change in angular displacement or rate of rotation

64
Q

Equation for angular velocity?

A

angular displacement / time taken

65
Q

What is moment of inertia?

A

resistance of a body to change its state of angular motion or rotation.

66
Q

Moment of inertia equation?

A

sum of (mass x distribution of mass from axis of rotation)

67
Q

Moment of inertia units?

A

Kgm^2

68
Q

What two factors effect moment of inertia?

A

mass, distribution of mass from the axis of rotation

69
Q

If moment of inertia is high then what is angular velocity?

A

low as resistance to rotation is high

70
Q

What is angular velocity measured in?

A

degrees per second

71
Q

What is angular momentum?

A

quantity of angular motion possessed by a body

72
Q

equation for angular momentum?

A

moment of inertia x angular velocity

73
Q

What is angular momentum measured in?

A

kilogram metres squared degrees per second ( kgm^2deg/s )

74
Q

What is the conservation of angular momentum?

A

a conserved quantity which remains constant unless an external eccentric force or torque is applied

75
Q

What is the angular analogue of newtons first law of motion?

A

the angular equivalent of newtons first law of motion, which states: a rotating body will continue to turn about its axis of rotation with constant angular momentum unless acted upon by an eccentric force or torque