Biomechanics - Everything Flashcards
(110 cards)
1
Q
How many laws of motion are there?
A
3
2
Q
What are the three laws of motion by Isaac newton?
A
law of inertia
law of acceleration
law of reaction
3
Q
what is newton’s first law?
A
law of inertia
4
Q
explain 1st law
inertia
A
a body continued in a state of rest or uniform velocity unless acted upon by an external or unbalanced force
5
Q
what happens to inertia if the mass is bigger?
A
the bigger the mass
the bigger the inertia
6
Q
use a sprinter as an example of inertia
A
-the runner will stay in the blocks until an external source big enough to overcome inertia creates motion
-they will then remain in a constant velocity until and an external or unbalanced force acts upon them
-inside running tracks have padded walls
7
Q
what is newton’s second law?
A
law of acceleration
8
Q
explain 2nd law
acceleration
A
a vista rate of acceleration is directly proportional to the size and the direction of the force applied
9
Q
law of acceleration
what happens if there’s a greater force?
A
greater force = greater acceleration
10
Q
law of acceleration
what happens if there’s body has a greater mass?
A
greater mass means a greater force is required
11
Q
use a sprinter as an example for law of acceleration
A
the greater force applied to the sprinter the greater rate of change in momentum and therefore acceleration away from the blocks. the force is applied in a forward direction so the sprinter drives towards the line
12
Q
what is newton’s third law?
A
law of reaction
13
Q
explain the third law
law of reaction
A
for every action force, there is an equal and opposite reaction force
14
Q
use rugby for the third law example
A
a forward and upward action is applied to the rugby ball from the rugby players foot.
the rugby ball will apply an equal and opposite action down and backward into the players foot
15
Q
exam question 3 marks
define newtons third law of motion and apply it to a sporting example
A
- for every action force there is an equal and opposite reaction force
- shot putter applies force to a shot
- the shot applied an equal and opposite reaction force to the shot putter
16
Q
exam question 3 marks
hockey players hit the ball at high speeds to prevent interceptions.
apply newton’s second law of motion to show how a hockey player may maximise the balls accelerations
A
- acceleration is directly proportional to the force applied
- the hockey player applies a large force to increase acceleration
- player may use a heavier stick to increase force
17
Q
A
18
Q
what is displacement?
A
is the length of a straight line joining the start and finish points
it is the shortest straight line route
19
Q
define velocity
A
velocity is the rate of change in displacement
20
Q
what is the calculation for velocity?
A
velocity = displacement / time taken
21
Q
what is velocity measured in?
A
m/s
metres per second
22
Q
is usain bolt runs 100m in 9.58 seconds
what’s his velocity?
A
10.44 m/s
100m / 9.58s =10.438 m/s
23
Q
define momentum
A
momentum is the quantity of motion possessed by a moving body
24
Q
what’s the momentum calculation?
A
momentum = mass X velocity
25
what is momentum measured in?
kilogram metres per second
Kgm/S
26
Usain Bolt is 94kg
he completes 100m sprint in 9.58 seconds
his average velocity is 10.44m/s
what’s his momentum?
981.36 kgm/s
94kg X 10.44 M/S = 981.36 Kgm/s
27
define acceleration
acceleration is the rate of change in velocity
28
what’s the equation for acceleration?
(final velocity - initial velocity) / time taken
29
what’s acceleration measured in?
m/s/s
metres per second per second
30
when usain bolt achieved his pro’s al best, his split time over the first 20m was 2.88s. his average velocity at 20n was 6.94 m/s and his velocity at 0n was 0m/s
calculate usain bolt’s acceleration over the first 20m
2.41 m/s/s
(6.94 - 0) /2.88 =2.41 m/s/s
31
define force
force is a push or pull that alters the state of motion of a body
32
what’s the calculation for force,
force = mass X acceleration
33
what is force measured in?
N
Newtons
34
why are the 2 types of force,
internal
external
35
what is internal force?
internal forces are generated by contraction of skeletal muscle
36
what’s a sporting example of an internal force?
a 100m sprinter must contact the rectus femoris to extend the knee and gastrocnemius to planterflex the ankle to generate the force required to accelerate from the blocks
37
what is external force?
comes from outside the body.
we consider the forces of
weight
reaction
friction
air resistance
38
what can forces do?
create motion
cause acceleration
cause deceleration
cause a change in direction
cause a change in shape
39
what is net force?
or resultant force?
the sum of all forces acting on a body,
it is the overall force acting on a body when all individual forces have been considered
40
what kind of external forces are there?
vertical forces
horizontal forces
41
what does it mean if the net force is 0?
there is no change munition as the forces are balanced.
body is either at rest or at a constant velocity
42
sporting example of a resultant force being 0?
a rugby scrum
if both packs are equally weighted and push with an equal force. the net force will be 0 and there will be no resulting motion
43
what happens if net force is positive?
the body will accelerate
44
what happens if the net force is negative?
it will decelerate
45
use netball as a sporting example of unbalanced forces
when a net baller makes a chest pass, the forwards force applied to the ball is far greater than any air resistance so accelerates to the teammate
46
use badminton as a sporting example of unbalanced forces
when a shuttle cock is hit hard, it will decelerate rapidly as air resistance acts in the opposite direction to motion
47
define weight
weight is the gravitation pull that the earth exerts on a body and is measured in Newtons N
48
what is weight measured in?
Newtons N
49
when is weight present?
weight force is ALWAYS present
acts downwards from the body’s centre of mass
50
how do you show weight on a diagram?
vertical arrow extending from the centre of mass downwards
51
what’s the weight calculation?
weight N = mass Kg X acceleration m/s/s
52
john had a mass of 73kg.
acceleration due to gravity is 10m/s/s
what his weight?
730N
73 X 10
53
what is reaction?
reaction is the equal and opposite force exerted by a body in response to the action force placed upon it and is measured in Newtons N
54
how do you show reaction on a diagram?
a vertical arrow extending upwards from the points of contact of the surface
55
what is friction?
it occurred when 2 surfaces slice over one another
measured in Newtons N
56
57
what direction does friction work in?
the opposite direction to motion
58
friction
is a sprint cyclists tyres tend to slip backwards as they rotate
which way does friction act?
friction opposes this and acts forwards
59
what does friction act parallel to?
acts parallel to the 2 surfaces in contact
60
how do you draw friction on a diagram?
same direction as motion from the point of contact parallel to the sliding surface
61
what is section effected by?
-roughness of the ground surface
-roughness of the contact surface
-temperature
-size of normal reaction
62
how does roughness of the ground surface impact friction?
increased roughness means increased friction
63
how does roughness of the contact surface impact friction?
sprinters, throwers and jumpers all wear spikes to increase friction
64
how does temperature impact friction?
by increasing temperature if either ground or contact surface
the diction is increased
65
what’s an example of increasing temperature to increase friction?
F1 drivers complete a formation lap to warm up tyres and track surface
66
how does the size of normal reaction impact friction?
by increasing normal reaction, friction is increased
67
what is air resistance?
a source that opposes motion of a body travelling through the air
a form of fluid friction
measured in Newtons N
68
what is air resistance measured in?
Newtons N
69
how do you show air resistance on a diagram?
horizontal arrow extending against the direction of motion from the centre of mass
70
what are the 4 factors affecting air resistance?
-velocity
-shape
-smoothness of surface
-frontal cross sectional area
71
smoothness of surface
how does it impact air resistance?
by increasing the smoothness, the air resistance decreases
72
frontal cross sectional area
how does it impact air resistance?
decreasing the frontal cross sectional area
air resistance decreases
73
velocity
how does it impact air resistance?
increased velocity means increased air resistance
74
shape
how does it impact air resistance?
the more aerodynamic the shape, the lower the surface resistance.
many sports use a teardrop or aerogel shape to minimise air resistance
75
what are the vertical forces?
weight and reaction
76
what are the horizontal forces?
friction and air resistance
77
what can technology in sport improve?
performance
training
recovery
faurnourcines
inclusion
participation
safety
comfort
analysis
understanding
entertainment
78
what are the 3 areas biomechanic technology can be split into?
limb kinematics
force plates
wind tunnels
79
what are limb kinematics?
the study of movement in relation to time and space
80
how does limb kinematics work?
multiple cameras record an athlete performing a skill
3D motion analysis records a person performing motion - sporting movement
81
what does limb kinematic evaluate?
the limb and joint efficiency
-bone geometry
-displacement
-velocity
-acceleration
in multiple planes are all measured
82
how does limb kinematics work?
-reflective markers are placed on the body’s joints
-filmed through videos and infra red cameras
-this is then sent through to computer software
-the data is immediately produced and is very accurate
-can analyse the technique if a specific limb or equipment through the different phases
83
what are the advantages of limb kinematics?
highly accurate
immediate data
easily interpreted
can focus on specific limbs
can focus on the different skill phases
84
what are the disadvantages of limb kinematics?
-expensive equipment
-specialised equipment/software
-essential training to use
-accuracy is dependent on correct placement of markers
-difficult to use on some skills due to lab requirements
85
what are force plates used for?
used to measure the ground reaction forces
86
what can the data from force plates be used for?
data can used to assess size and direction of forces acting on athletes
87
why are force plates used?
to asses human motion, balance, rehabilitation and for physical therapy
88
what is a force plate?
it is a metal plate with force transducers that displays an electrical output proportional to the force applied
89
what are the five reasons force plates are used?
biomechanical assessment
gait analysis (analysis of human motion)
balance
rehabilitation
physical therapy
90
what are the advantages of force plates?
-highly accurate
-immediate data
-easily interpreted
-can be displayed in all planes of movement
91
what are the disadvantages of force plates?
-expensive equipment
-specialised equipment / software
-difficult to use in some skills due to lab requirements
-may require adapted movement by performer to accommodate plate
92
why would you use a wind tunnel?
-objects and techniques can be tested for aerodynamic efficiency
-forces produced by the air on an object can be measured
-the flow of the air around an object is also studied
-used to improve aerodynamics if an object or technique
93
in wind tunnels how do they study the flow of the air around an object?
they use smoke or coloured air
94
why would someone use wind tunnels?
to improve streamlining and affects lift and drag
95
why are the advantages of wind tunnels?
-allows control of the environmental variables
-precise measurements
-time efficient
96
why are the disadvantages of wind tunnels?
-expensive
-specialised facilities / equipment
-requires specialists to carry out testing
97
what is centre of mass?
the point at which a body is balanced in all directions
98
if you lift your right arm up to the side, where is the centre of mass
it moves to the right
naval height
99
why was the fosbury flip in high jump made?
so that greater heights could be achieved.
by arching their back, the COM will move outside their body
100
does the COM have to be within actual physical matter?
no
101
can the COM act as a point of rotation?
yes
can move outside the body and act as a point of rotation
102
an example of the COM being used as a point of rotation
a gymnast perfuming a front tucked somersault moves their centre of mass infront of the body and rotates around it
103
what is stability?
the ability of a body to resist motion and remain at rest
also the ability of a body to withstand a force applied and return to its original position without damage
104
are stability and centre of mass connected?
yes
105
what factors impact stability?
heigh of COM
mass
base of support
line of gravity
106
how does the height of the centre of mass impact the stability?
the lower the centre of mass, the more stable it is
107
example of the height of COM having an impact?
when a gymnast lands a jump they flex their knees and up to lower their centre of mass and achieve a more stable landing
108
what is line of gravity?
an imaginary line which extends from the centre of mass downwards to the floor
the more central the line of gravity to the base of support, the greater the stability
109
what’s an example of line of gravity in a sporting setting?
judo players will try keep their centre of mass above their base of support to make them more stable
110
how do your draw base of support on a diagram?
a circle around the base of support
