# PAPER 1 - Biomechanics Flashcards

1
Q

Define Newton’s First law of motion : INERTIA

A

a body continues in a STATE OF REST or UNIFORM VELOCITY unless acted upon by an EXTERNAL or UNBALANCED FORCE

2
Q

Define Newton’s Second law of motion : ACCELERATION

A

a body’s RATE OF CHANGE in MOMENTUM is PROPORTIONAL to the SIZE of the FORCE applied and acts in the SAME DIRECTION as the force applied

3
Q

Define Newton’s Third law of motion : REACTION

A

for every ACTION FORCE applied to a body there is an EQUAL and OPPOSITE reaction force

4
Q

What is the equation for VELOCITY ?

A

velocity = displacement / time taken

5
Q

What is the equation for MOMENTUM ?

A

momentum = mass x velocity

6
Q

What is the equation for ACCELERATION ?

A

acceleration = (final velocity - initial velocity) / time taken

7
Q

What is the equation for FORCE ?

A

force = mass x acceleration

8
Q

Define FORCE

A

a PUSH or PULL that ALTERS that state of motion of a body

9
Q

Define INTERTIA

A

the RESISTANCE of a body to CHANGE its state of motion, whether at rest or while moving

10
Q

Define VELOCITY

A

the RATE OF CHANGE in DISPLACEMENT

11
Q

Define MOMENTUM

A

the QUANTITY of MOTION possessed by a body

12
Q

Define ACCELERATION

A

the RATE OF CHANGE in VELOCITY

13
Q

Define WEIGHT

A

GRAVITATIONAL PULL that the earth exerts on the body - (N)

14
Q

Define REACTION

A

EQUAL AND OPPOSITE FORCE in response to the action force placed upon it

15
Q

Define FRICTION

A

the force that OPPOSES the motion of TWO SURFACES in contact

16
Q

Define AIR RESISTANCE

A

a force that OPPOSES the MOTION of a body TRAVELLING through the air

17
Q

What are LIMB KINETICS ?

A
• study movement in relation to TIME AND SPACE

- white dots

18
Q

What are FORCE PLATES ?

A
• measure ground reaction forces
19
Q

What are WIND TUNNELS ?

A
• test aerodynamic efficiency

- measure air resistance

20
Q

Define CENTRE OF MASS

A

the point at which a body is BALANCED in ALL DIRECTIONS

21
Q

How do you increase stability ?

A
• increase mass = increase inertia
• decrease CoM
• increase BoS
• more central LoG
22
Q

Define LINE OF GRAVITY

A

imaginary line that extends from the COM downwards to the FLOOR

23
Q

What is a FIRST CLASS lever ?

A

24
Q

What is a SECOND CLASS lever ?

A

25
Q

What is a THIRD CLASS lever ?

A

26
Q

What is the EFFORT ARM ?

A

distance from the FULCRUM to the EFFORT

27
Q

What is the LOAD ARM ?

A

distance from the LOAD to the FULCRUM

28
Q

A

SECOND CLASS

• effort arm is greater than the load arm
• large load / small effort
• slower
29
Q

A

THIRD CLASS

• load arm is greater than effort arm
• small load / large effort
• faster
30
Q

What is an INTERNAL FORCE ?

A

generated by the CONTRACTION of SKELETAL MUSCLE

31
Q

INTERNAL FORCE : EXAMPLE

A

100m - contract rectus femoris - extend knee - drive away from the blocks

32
Q

What is an EXTERNAL FORCE ?

A

comes from OUTSIDE the body and acts upon it

33
Q

What are the 4 examples of EXTERNAL FORCES ?

A
• weight
• reaction
• friction
• air resistance
34
Q

What are the 5 effects of FORCE ?

A
• create motion
• accelerate a body
• decelerate a body
• changing the direction
• changing the shape
35
Q

Using a football penalty as an example: how does force (1) CREATE MOTION ?

A

the football will remain at rest on the penalty spot until a force is applied to it

36
Q

Using a football penalty as an example: how does force (2) ACCELERATE A BODY ?

A

the greater the force applied by the footballer’s foot to the ball, the greater the rate of acceleration towards the goal

37
Q

Using a football penalty as an example: how does force (3) DECELERATE A BODY ?

A

as the ball moves through the air towards the goal, the force of AIR RESISTANCE will act in the OPPOSITE direction and slow it down

38
Q

Using a football penalty as an example: how does force (4) CHANGE THE DIRECTION OF A BODY ?

A

as the goalkeeper dives to save a high corner shot, he will apply force from his HANDS to the BALL, changing it’s direction pushing it AWAY from the goal

39
Q

Using a football penalty as an example: how does force (5) CHANGE THE SHAPE OF A BODY ?

A

if the goalkeeper fails to make the save, the force of the ball coming into contact with the NET will change the shape of the net.

40
Q

What is NET FORCE ? (resultant force)

A

sum of all the forces action on a body - when all individual forces have been considered

41
Q

What is the net force when forces are BALANCED ?

A

net force = 0

42
Q

What are BALANCED FORCES ?

A

two or more forces action on a body are EQUAL IN SIZE and OPPOSITE IN DIRECTION

43
Q

What are UNBALANCED FORCES ?

A

two or more forces UNEQUAL IN SIZE and OPPOSITE IN DIRECTION = net force

44
Q

What are the 2 VERTICAL FORCES ?

A

weight

reaction

45
Q

What is the equation for WEIGHT ?

A

mass x acceleration due to gravity

46
Q

What are the 2 HORIZONTAL FORCES ?

A

friction

air resistance

47
Q

What 4 factors affect FRICTION ?

A
• roughness of ground surface
• roughness of contact surface
• temperature
• size of normal reaction
48
Q

How does (1) ROUGHNESS OF GROUND SURFACE affect friction ?

A

increasing roughness = increased friction

49
Q

How does (2) ROUGHNESS OF CONTACT SURFACE affect friction ?

A

increasing roughness = increasing friction

50
Q

How does (3) TEMPERATURE affect friction ?

A

increasing temperature = increasing friction

e.g. F1 drivers have warm up lap

51
Q

How does (4) SIZE OF NORMAL REACTION affect friction ?

A

increasing normal reaction = increasing friction

e.g. shot-putters have high mass - equal / opposite high reaction force - greater friction - prevents over-rotation

52
Q

What 4 factors is AIR RESISTANCE affected by ?

A
• velocity
• shape
• frontal cross-sectional area
• smoothness of surface
53
Q

How does (1) VELOCITY affect air resistance ?

A

increasing velocity = increasing air resistance

54
Q

How does (2) SHAPE affect air resistance ?

A

increased aerodynamic = decreasing air resistance

55
Q

What is STREAMLINING ?

A

creation of SMOOTH AIR FLOW around an AERODYNAMIC shape to minimise air resistance

56
Q

How does (3) FRONTAL CROSS-SECTIONAL AREA affect air resistance ?

A

decreasing frontal cross-sectional area = decreasing air resistance

57
Q

How does (4) SMOOTHNESS OF SURFACE affect air resistance ?

A

increasing smoothness = decreasing air resistance

58
Q

What are the units for velocity ?

A

metres per second - m/s

59
Q

What are the units for acceleration ?

A

metres per second per second - m/s/s

60
Q

What are the units for momentum ?

A

kilogram metres per second - kgm/s

61
Q

What are the units for force ?

A

newtons - N

62
Q

What are the units for weight ?

A

newtons - N

63
Q

What is RELIABILITY ?

A

the extent to which an experiments produces the SAME RESULT after REPEATED TRIALS

64
Q

What is VALIDITY ?

A

how well a test measures what it claims to measure = accurate application and interpretation

65
Q

What is LINEAR MOTION ?

A

movement of a body in a STRAIGHT or CURVED line, where all parts move the SAME DISTANCE, in the SAME DIRECTION over the SAME TIME

66
Q

What is DIRECT FORCE ?

A

a force applied through the CoM resulting in LINEAR MOTION

67
Q

What is DISTANCE ?

A

the total length covered from start to finish (m)

68
Q

What is DISPLACEMENT ?

A

the shortest straight-line route from start to finish (m)

69
Q

What is SPEED ?

A

the rate of change in DISTANCE (m/s)

70
Q

What is a DISTANCE/TIME graph ?

A

a visual representation of the DISTANCE travelled plotted AGAINST the TIME taken

71
Q

What is a SPEED/TIME graph ?

A

a visual representation of the SPEED OF MOTION plotted AGAINST the TIME taken

72
Q

What is VELOCITY/TIME graph ?

A

a visual representation of the VELOCITY OF MOTION plotted against the TIME taken

73
Q

What is ANGULAR MOTION ?

A

movement of a body or part of a body in a CIRCULAR PATH about an AXIS OF ROTATION

74
Q

What is an ECCENTRIC FORCE ?

A

a force applied OUTSIDE the CoM, resulting in ANGULAR MOTION

75
Q

What is a TORQUE ?

A

a MEASURE of the TURNING force applied to a body

76
Q

What is a sporting example of linear motion ?

A

skeleton bob at top speed

77
Q

What is a sporting example of angular motion ?

A

gymnastic somersault

78
Q

Where does the LONGITUDINAL AXIS run ?

A

from head to toe (through the CoM)

79
Q

Where does the TRANSVERSE AXIS run ?

A

from left to right (through the CoM)

80
Q

Where does the FRONTAL AXIS run ?

A

from front to back (through the CoM)

81
Q

What sport skill occurs in the longitudinal axis ?

A

flat spin on ice

82
Q

What sport skill occurs in the transverse axis ?

A

somersault

83
Q

What sport skill occurs in the frontal axis ?

A

cartwheel

84
Q

What is ANGULAR VELOCITY ?

A

the rate of change in ANGULAR DISPLACEMENT (radians per second)

85
Q

What is MOMENT OF INERTIA ?

A

the RESISTANCE of a body to change its state of ANGULAR MOTION or ROTATION

86
Q

How do you calculate moment of inertia ?

A

mass x distance from axis

87
Q

What is ANGULAR MOMENTUM ?

A

the QUANTITY of ANGULAR MOTION possessed by a body