PAPER 1 - Biomechanics Flashcards
(154 cards)
1
Q
Define Newton’s First law of motion : INERTIA
A
body continues in a STATE OF REST/UNIFORM VELOCITY unless acted upon by an EXTERNAL/UNBALANCED FORCE
2
Q
Define Newton’s Second law of motion : ACCELERATION
A
- body’s RATE OF CHANGE in MOMENTUM = k(SIZE + Direction of FORCE applied)
3
Q
Define Newton’s Third law of motion : REACTION
A
- every ACTION FORCE applied to a body has an EQUAL + OPPOSITE reaction force
4
Q
What is the equation for VELOCITY ?
Units
A
displacement / time taken
m/s
5
Q
What is the equation for MOMENTUM ?
Units?
A
- mass x velocity
kgm/s
6
Q
What is the equation for ACCELERATION ?
Units?
A
acceleration = (final velocity - initial velocity) / time taken
m/s^2
7
Q
What is the equation for FORCE ?
Units?
A
force = mass x acceleration
Newtons
8
Q
Define FORCE
A
a PUSH or PULL that ALTERS a body’s state of motion
9
Q
Define INERTIA
A
RESISTANCE of a body to CHANGE its state of motion, 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 moving body
12
Q
Define ACCELERATION
A
the RATE OF CHANGE in VELOCITY
13
Q
Define WEIGHT
A
GRAVITATIONAL PULL that the earth exerts on a body
14
Q
Define REACTION
A
- EQUAL+OPPOSITE FORCE in exerted by a body in response to action force placed upon it
15
Q
Define FRICTION
A
- Force that OPPOSES the motion of TWO SURFACES in contact
16
Q
Define AIR RESISTANCE
A
a force that OPPOSES that MOTION through the air
17
Q
What are LIMB KINEMATICS ?
A
- study of movement in relation to TIME AND SPACE
18
Q
What are FORCE PLATES ?
A
- measure ground reaction forces
19
Q
What are the functions of WIND TUNNELS ?
A
- test aerodynamic efficiency
- measure air resistance
20
Q
Define LINE OF GRAVITY
A
imaginary line that extends from CoM to the FLOOR
21
Q
What is a FIRST CLASS lever ?
A
effort - fulcrum - load
22
Q
What is a SECOND CLASS lever ?
A
effort - load - fulcrum
23
Q
What is a THIRD CLASS lever ?
A
load - effort - fulcrum
24
Q
What is the EFFORT ARM ?
A
distance from FULCRUM to EFFORT
25
What is the LOAD ARM ?
distance from LOAD to FULCRUM
26
What is MECHANICAL ADVANTAGE ?
Which lever acts at one?
- EA > LA
- 2nd class
- Large Load w/small effort
27
What is MECHANICAL DISADVANTAGE ?
Which lever acts as one?
- LA > EA
- small load w/large effort
- Third Class
28
What is an INTERNAL FORCE ?
- Force generated by the CONTRACTION of SKELETAL MUSCLE
29
What is an EXTERNAL FORCE ?
comes from OUTSIDE the body and acts upon it
30
What are the 4 examples of EXTERNAL FORCES ?
- weight
- reaction
- friction
- air resistance
31
What are the 5 effects of FORCE ?
- create motion
- accelerate a body
- decelerate a body
- changing direction
- changing shape
32
how does force CREATE MOTION ?
- football will remain at rest on the penalty spot until a force is applied to it
33
how does force ACCELERATE A BODY ?
the greater the force applied by the foot on the ball, the greater it accelerates towards the goal
34
how does force DECELERATE A BODY ?
- force of the foot on the ball = force of the ball on the foot
35
how does force CHANGE THE DIRECTION OF A BODY ?
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
36
how does force CHANGE THE SHAPE OF A BODY ?
- force of the ball coming into contact with NET will change the shape of the net.
37
What is NET FORCE ? (resultant force)
sum of all the forces acting on a body - when all individual forces are considered
| Resultant Force
38
What happens when the net force is 0?
- No change in motion as all forces are balanced
39
Define BALANCED FORCES
two or more forces acting on a body that are EQUAL IN SIZE and OPPOSITE IN DIRECTION
40
What are UNBALANCED FORCES ?
two or more forces UNEQUAL IN SIZE + OPPOSITE IN DIRECTION
41
What are the 2 VERTICAL FORCES ?
- weight
- reaction
42
equation for WEIGHT ?
| Units?
mass x acceleration due to gravity
| N
43
What are the 2 HORIZONTAL FORCES ?
friction
air resistance
44
How does VELOCITY affect air resistance ?
increased velocity of cyclist = increased air resistance
45
How does SHAPE affect air resistance of a cyclist ?
tear-drop helmet = decreased air resistance
46
What is STREAMLINING ?
SMOOTH AIR FLOW created around an AERODYNAMIC shape to minimise air resistance
47
How does FRONTAL CROSS-SECTIONAL AREA affect air resistance ?
low crouched position of downhill skier = decreases air resistance
48
How does SMOOTHNESS OF SURFACE affect air resistance ?
smooth lycra suits = decreased air resistance
49
What is DIRECT FORCE ?
- force applied through CoM resulting in LINEAR MOTION
50
What is DISTANCE ? w/units
- total length covered from start to finish (m)
51
What is DISPLACEMENT ?
| (units)
- shortest straight-line route from start to finish (m)
52
What is SPEED ?
| units
the rate of change in DISTANCE
| m/s
53
What is a DISTANCE/TIME graph ?
- DISTANCE travelled plotted AGAINST TIME taken
54
What is a SPEED/TIME graph ?
- SPEED OF MOTION plotted AGAINST the TIME taken
55
What is VELOCITY/TIME graph ?
- VELOCITY OF MOTION plotted against the TIME taken
56
What is ANGULAR MOTION ?
- movement of a body/body part in a CIRCULAR PATH about an AXIS OF ROTATION
57
What is an ECCENTRIC FORCE ?
a force applied OUTSIDE the CoM, resulting in ANGULAR MOTION
58
What is TORQUE ?
a MEASURE of the TURNING force applied to a body
59
What is a sporting example of linear motion ?
skeleton bob at top speed
60
What is a sporting example of angular motion ?
somersault, gymnastics
61
Where does the LONGITUDINAL AXIS run ?
from top to bottom of the body
62
Where does the TRANSVERSE AXIS run ?
from side to side
63
Where does the FRONTAL AXIS run ?
from front to back of the body
64
What sport skill occurs in the longitudinal axis ?
- full twist on trampoline
65
What sport skill occurs in the transverse axis ?
somersault on trampoline
66
What sport skill occurs in the frontal axis ?
cartwheel in gymnastics
67
What is ANGULAR VELOCITY ?
| w/units
the rate of change in ANGULAR DISPLACEMENT
| (radians per second)
68
What is MOMENT OF INERTIA ?
| units
- RESISTANCE of a body to change its state of ANGULAR MOTION
| kgm^2
69
How do you calculate moment of inertia ?
sum(mass x distribution of mass from axis of rotation)
70
What is ANGULAR MOMENTUM ?
| units
- QUANTITY of ANGULAR MOTION possessed by a body
| kgm^2/s
71
4 types of spin on an object
Topspin
Backspin
Sidespin Hook
Sidespin Slice
72
Topspin w/effect on a projectile
- Eccentric force applied above COM
- Shortens flight path of projectile
73
Backspin w/effect on a projectile
- Eccentric force applied below CoM
- Lengthens flight path of a projectile
74
Sidespin Hook w/effect on projectile
- Eccentric Force applied right of COM
- deviates flight path to the left
75
Sidespin Slice w/effect on projectile
- Eccentric Force applied left of COM
- deviates flight path to the right
76
Equation for Force
| Units
Mass X Acceleration
| N
77
Equation for Momentum
| Units
Mass X Velocity
| Kg
78
Equation for Acceleration
| Units
(Final Velocity - Initial Velocity)/time taken
| m/s^2
79
Equation for Weight
| Units
Mass X Gravitational field strength
| N
80
4 factors impacting magnitude of air resistance/drag on a body or object
- velocity
- frontal cross-sectional area
- streamlining + shape
- surface characteristics.
81
Equation for Angular Momentum
Moment of Inertia X Angular Velocity
82
Object with a parabolic flight path
Shotput
83
Object with a non-parabolic flight path
badminton shuttle
84
what happens when a net force is present?
- Change in motion as forces are unbalanced
85
What are external forces split into?
- horizontal / vertical
86
4 factors affecting friction
- Roughness of ground surface
- Roughness of contact surface
- Temperature
- Size of normal reaction
87
Example of roughness of ground surface affecting friction?
- Athletes run on rough, rubberised tracks
88
Example of roughness of the contact surface affecting friction
- Athletes wear spiked shoes
89
Example of temperature affecting friction
- F1 drivers have warm-up lap to increase tyre temp.
90
Example of normal reaction size affecting friction
Shot putters have high mass = high equal + opposite reaction force
91
Origin + Direction of Weight Arrow
- From CoM extending vertically downwards
92
Origin + Direction of Reaction Arrow
- From point of contact extending vertically upwards
93
Origin + Direction of Friction Arrow
- From point of contact extending horizontally in same direction as motion
94
Origin + Direction of Air Resistance
From CoM extending horizontally against the direction of motion
95
Define Centre of Mass
- point at which an object/body is balanced in all directions
96
4 Factors affecting stability
- Mass of body
- Height of CoM
- Size of base of support
- Line of Gravity
97
How does mass affect stability?
- Greater mass = greater inertia
- E.G. Sumo wrestler
98
How does height of CoM affect stability?
- lower CoM = greater stability
99
How does size of base of support affect stability?
- More points of contact = wider base of suport + stability
100
How does line of gravity affect stability?
- More central = more stability
101
Example of when stability is maximised
- Sprinter preparing in blocks
102
Example of when stability is minimised
- Sprinter falling forwards when gun is fired
103
2 main functions of lever systems
- generate muscular effort to overcome a given load
- increase speed of given movement
104
Example of First Class Lever
- Extension of neck during header in football
105
Example of Second Class Lever
- Ball of foot in high jump take off
106
Example of third class lever
- Flexion of elbow during bicep curl
107
Define Limb Kinematics
- Study of movement in relation to time + space
108
Define Force Plates
- Measure ground reaction forces in lab conditions
109
Define Wind Tunnels
- Steel fame buildings w/wide fans
- produce artificial wind
110
1 use of Limb Kinematics
- 3D analysis evaluates
- Movement Efficiency
111
1 use of Force plates
Assess size + direction of forces acting on athlete
112
1 use of wind tunnels
- F1 cars tested for aerodynamic efficiency
113
1 way of optimising performance with limb kinematics
- data produced improves performance
114
1 way of optimising performance with force plates
- Balance rehab + physiotherapy
115
1 way of optimising performance using wind tunnels
- Improving air flow around objects
116
Equation for speed w/units
Distance/time taken - m/s
117
Define Linear Motion
- Movement of a body in a straight/curved line, where all parts move in same direction, distance + time
118
Define Gradient
Slope of a graph at a particular moment in time
119
Equation for Angular Momentum
MI x Angular Velocity
120
2 factors affecting the size of the MOI of a rotating body
- mass of the body
- distribution of mass from axis of rotation
121
How does the mass of the body affect MOI
Greater mass = Greater MOI
122
How does distribution of mass affect MI
- Further mass from axis of rotation = greater MI
123
What happens if MOI is high?
- High resistance to rotation
- Low AV
- Slower rate of spin
124
What happens if MOI is low?
- Low resistance to rotation
- High AV
- Faster rate of spin
125
Define Conservation of Angular Momentum
- remains constant unless an external eccentric force/torque is applied
126
Which one of Newtons laws does angular momentum relate to + what does it state
- 1st law - rotating body will continue to turn about its axis of rotation
127
What happens during take-off + landing phase of a triple axel jump in ice skating
- Distribution of mass is away from longitudinal axis
- MOI is high
- AV is low
128
What happens during flight phase of the triple axel jump in ice skating
- Distribution of mass is close to longitudinal axis
- MOI is low
- AV is high
129
Define Drag
- Force that opposes the direction of motion of a body through water
130
4 factors affecting horizontal distance travelled by a projectile
- Speed of release
- Angle of release
- Height of release
- Aerodynamic factors
131
How does speed of release affect the horizontal distance of a projectile and which law does it link to?
- greater outgoing speed = greater distance
- 2nd Law
132
How does angle of release affect horizontal distance of a projectile
- 45 degrees optimises horizontal distance
133
How does height of release affect horizontal distance of a projectile
- Release height>landing height = <45 degrees
- release height< landing height = >45 degrees
- release height = landing height = 45 degrees
134
Which 2 aerodynamic forces affect the horizontal height of a projectile?
- Bernoulli Force
- Magnus Force
135
Define Parabolic Flight path
- Symmectrical flight path about its highest point caused by AR on a projectile
136
Define Non-Parabolic Flight Path
- Asymmetrical flight path about its highest point caused by AR on a projectile
137
Define Aerofoil
- Streamlined shape w/curved upper surface + flat lower surface adding lift to a body
138
Define Lift Force
- Additional force created by a pressure gradient, increasing the time a projectile hangs in air
139
Define Angle of Attack
- optimises lift force of a projectile due to bernoulli principle
140
Define Magnus Force
- Force created by pressure gradient acting on a spinning body moving through the air
141
Example of an object that creates an upwards lift force
Discus
142
Example of an object that creates a downwards lift force
- F1 Racecar at high speeds around corners
143
How is spin created?
Applying an external force outside CoM
144
Effect of topspin rotation on magnus force
- Downwards MF = shortened flight path
145
Effect of magnus force on backspin rotation
- MF Upwards = lengthens flight path
146
Effect of sidespin rotation on Magnus Force
- MF to right + left = slice/hook
147
What happens above an aerofoil?
- Air velocity + distance increases, pressure decreases
148
What happens below an inverted aerofoil?
- Air velocity + distance increases
- pressure decreases
149
What happens below an aerofoil?
- Air velocity + distance decreases, pressure increases
150
What happens above an inverted aerofoil?
- Air velocity + distance decreases, pressure increases
151
What is common between the bernoulli lift force and magnus force?
- Air always opposes the direction of motion
152
How is linear motion created
- Direct force applied through CoM
153
How is Angular Motion created?
- Eccentric force applied outside the CoM
154
Balanced forces
- Forces that are equal in size + opposite in direction
