Biomechanical Principles and Levers (Paper 2) Flashcards
1
Q
What does a lever consist of
A
Fulcrum
Load
Effort
2
Q
What represents the levers
A
Bones
3
Q
What represents joints
A
Fulcrum
4
Q
What represents the effort
A
The muscle
5
Q
What represents the load
A
The weight of body part being moved/resistance
6
Q
What are the three types of levers
A
First class lever
Second class lever
Third class lever
7
Q
What does each classification of the levers depend on
A
The position of the fulcrum, load and effort in relation to each other
8
Q
What is located on the centre of a first class lever
A
The fulcrum
9
Q
What are the two examples of first class levers in the body
A
Movement of head and neck during flexion and extension
Extension of the elbow
10
Q
What is located in the middle of a second class lever
A
The load
11
Q
Give an example of a second class lever
A
Plantar flexion of the ankle
12
Q
What is located in the middle of a third class lever
A
The effort
13
Q
Give examples of third class levers in the body
A
Hip, knee and elbow flexion
(Most levers in the body are third class)
14
Q
What is the effort arm
A
The length of the line between where the fulcrum and effort are labelled
15
Q
What is the load arm
A
The length of the line between where the fulcrum and the load are labelled
16
Q
What is a mechanical disadvanatge
A
-When the load arm of a lever is longer than the effort arm
-the lever system cannot move as heavy a load but can do it faster
-large range of movement
17
Q
What is mechanical advantage
A
-When the effort arm is longer than the load arm
-means that the lever system can move a large load over a short distance and requires little force
-Small range of movement
-difficult to generate speed and distance
18
Q
What is linear motion
A
Motion in a straight or curved line, with all body parts moving the same distance at the same speed in the same direction
19
Q
Give an example of linear motion
A
- 100m athlete will travel with linear motion in a straight line during their race
- 200m athlete will travel with linear motion in a curved line when running the bend
20
Q
What is inertia
A
The resistance an object has to a change in its state of motion
21
Q
What is Newton’s first law of inertia
A
A force is required to change the state of motion of an object
22
Q
What is Newton’s second law of acceleration
A
The magnitude (size) and direction of the force determines the magnitude and direction of the acceleration on an object
23
Q
What is Newton’s third law of motion
A
For every action (force) there is an equal opposite reaction (force)
24
Q
Give a sporting example of Newton’s first law
A
In the high jump, the athlete runs horizontally towards the bar and then changes their state of motion at take-off when they travel vertically to try and clear the bar
25
Give a sporting example of Newton’s second law of acceleration
To provide the acceleration at the start of a sprint race an athlete will have to apply a large force internally with their gluteals, quadriceps and gastrocnemius as they drive forward
26
Give a sporting example of Newton’s third law of motion
At the start of a sprint race the athlete pushes back in the blocks as hard as possible and the blocks push forward on the athlete and provides forward acceleration on the athlete
27
What is ground reaction force
The equal and opposite force exerted on a performer who applies a muscular force on the ground
28
What is a scalar quantity
When measurements are described in terms of just their size or magnitude
29
Give examples of scalar quantities
Speed, distance, mass, temperature
30
What is speed
The rate of change of position and can be calculated by speed = distance/time
31
What is distance
The length of the path a body follows when moving from one position to another
32
What is the centre of mass
- point of balance
- due to the irregular shape of human and it’s constant motion it is hard to identify this point
- e.g. raising your arm in the air raises the centre of mass to keep the body balance
- COM is usually in between the hip region when standing
33
What is the line of gravity
This is the line extending vertically downwards from the centre of mass and should be central over the base of support to increase stability
34
What factors affect your stability
- height of the centre of mass
- position of the line of gravity
- area of the support base
- Mass of the performer
35
What does the area of support base refer to
The amount of contact points of the person
36
How does lowering you centre of mass affect stability
It increases stability. A low stance makes it harder for an opponent to push you over
37
What is the mechanical advantage of a second class lever
- can generate much larger forces
38
What is the mechanical disadvantage of second class levers
- slow
- limited range of movement
39
What is the mechanical advantage of a first and third class lever
- large range of movement
- any resistance can be quickly moved
40
What is the mechanical disadvantage of first and third class levers
Cannot apply much force to move an object
41
what does a vector quantity refer to
when measurements are described in terms of their size and direction
42
give examples of scalar quantities
weight
momentum
dispalcement
43
how are vectors represented
by arrows, the length of which shows the magnitude
44
how is direction shown
by a line of application
point of application
and an arrow head
45
what is mass
- the scalar quantity of matter the body possesses
- measured in kg
46
what is weight
- the gravitational force exerted on an object (vector)
- measured in newtons
47
what is distance
measured in metres and is the path a body takes as it moves from the starting to the finishing position
48
what is displacement
measured in metres and is the shortest route in a straight line between the starting and finishing point
49
what is speed
- a measurement in m/s of the body movement per unit of time with no reference to direction
50
what is velocity
measured in m/s and is the rate of change of displacement
51
how do you calculate speed
speed(m/s) = distance(m) / time (s)
52
how is velocity calculated
velocity (m/s) = displacement (m) / time (s)
53
what is happening when a distance time graph shows a straight horizontal line
the performer/object is stationary
54
what is happening when a distance time graph shows a straight diagonal line
the performer is moving at a constant speed
55
what is happening when a distance time graph shows a line that is curved and gradually gets steeper
the performer is accelerating
56
what is happening when a distance time graph shows a steep curve and starts to becomes levelled off
the performer is decelerating
57
what does a distance time graph look like
distance on the y axis time on the x axis and then a line to represent the information
58
what does a constant velocity look like on a velocity time graph
a straight horizontal line
59
what does an accelerating velocity look like on a distance time graph
the gradient of the line gets steeper
60
what does a decelerating velocity look like on a distance time graph
a decreasing gradient
61
what happens when the line in the velocity time graph is above the x axis but then goes below the axis and returns to the x axis
this means there has been a change in direction
62
what is acceleration
the rate of change of velocity measured in m/s2
63
how is acceleration calculated
acceleration (m/s2) = change in velocity (m/s) / time (s)
64
how docalculate change in velocity
final velocity - initial velocity
65
what is momentum
the product of mass and velocity of an object
66
how do you calculate momentum
momentum (kg/s) = mass (kg) x velocity (m/s)
67
what two types of forces act upon a performer during linear motion
internal
external
68
what is an internal force
force generated by the skeletal muscles (e.g. quads contract concentrically to extend the knee in a jump)
69
what is an external force
a force coming from outside the body (friction, air resistance, weight)
70
what is the conservation of momentum
when momentum cant be changed. for example in flight neither mass or velocity can be altered so means momentum cant either
71
how can external forces be categorised as
- vertical
- horizontal
72
give an example of vertical force
weight
reaction force
73
give an example of horizontal force
- friction
- air resistance
74
what is reaction force
there is always a reaction force when two bodies are in contact with each other.
75
what is friction
a force that always opposes motion
76
what are the two types of friction
- static
- sliding
77
what is static friction
Force exerted when there is no motion between 2 surfaces
78
what is sliding friction
a force that occurs between two surfaces which are in contact and trying to move past each other.
79
What factors affect friction
- the roughness of the surface
- Mass of the object
- the temperature of the 2 surfaces
80
How does the roughness of the surface affect friction
The rougher the surface, the greater the friction.
81
How do athletics athletes increase friction
Athletics athletes wear spikes to increase friction and maximise acceleration.
82
How does the mass of an object affect friction
The greater the mass, the greater the friction: for example, mountain biking up a muddy hill, stand up over front driving wheel for better grip
83
How does the temperature of 2 surfaces affect friction
Increase in temperature, reduces the friction.
84
What is air resistance
A force that acts in the opposite direction to the motion of a body travelling through the air
85
What three things is air resistance dependant on
- velocity of the moving object
- frontal cross sectional area of the moving body
- the shape and surface of the moving body
86
How does the velocity of the object affect air resistance
The faster an object is moving, the more it is subject to air resistance.
87
How does the frontal cross sectional area of the moving body affect air resistance
The larger the frontal cross section the greater the effects of air resistance.
88
How does the shape and surface of the moving object affect air resistance
Streamlined shape = less resistance, as does a smooth surface
89
How are free body diagrams supposed to be shown
- Arrows straight and the length of the line represents how strong the force applied is
- arrows represent forces (weight, air resistance, friction, reaction)
90
What is net force
This is the resultant force acting on a body when all other forces have been considered
91
What is a balanced force
A balanced force is when there are 2 or more forces acting on a body that are equal in size but opposite in direction
92
What is an unbalanced force
An unbalanced force is created when a force acting in one direction is larger than the force acting in the opposite direction
93
What occurs when friction is greater than air resistance
Acceleration
94
What occurs when air resistance is greater than friction
Deceleration
95
What is a vector diagram
Diagrams that show the direction and magnitude of a vector, by vector arrows, on a graph
96
What is impulse
How long it takes for a force to be applied
97
How do you calculate impulse
Force x Time (measured in KG/s)
98
How is impulse linked to momentum
If the impulse increases so to does the rate of change of momentum. This will cause a large change in velocity
99
How do you use impulse to increase speed
- Increase the amount of internal muscular force applied.
- Increase the amount of time in which the force is applied (following thru in tennis to increase the time in contact with the ball)
100
How do you use impulse to decrease speed
Increase the time that the force acts on a body. For example, absorbing landing in gymnastics or pushing feet into the ground after 60m sprint.
101
What is a force time graph
- A graph to show impulse
- positive and negative on y axis
- time along the x
102
What is angular motion
Movement of a body in a circular path about an axis of rotation
103
How is angular motion created
By an eccentric force (a force applied outside the centre of mass, creating a rotating movement)
104
What are the axis of rotation
- transverse (Sagittal)
- Sagittal (frontal)
- longitudinal (transverse)
105
How does the Sagittal axis run
Front to back
106
Give an example of the movement around the Sagittal axis
A cartwheel
107
How does the transverse axis run
Side to side across the body
108
Give an example of movement around the transverse axis
Somersault
109
How does the longitudinal axis run
Top to bottom
110
Give an example of a movement in the longitudinal axis
Spinning in ice skating
111
Angular motion occurs as a result of…..
Torque/moment of force
112
What does torque cause
Torque is the turning force, it causes an object to turn about is axis of rotation
113
Torque is dependant on two things…
- size of the force, greater the size of force greater the torque
- application of the same force, if the same force is applied further away from the axis torque will be increased.
114
How is moment of force/torque calculated
torque (Nm) = Force (N) x Perpendicular distance to the fulcrum (m)
115
What does a body need to have to be in equilibrium
The resistance arm must equal the effort arm
116
How can newtons 1st law be related to angular motion
Every body continues in its state of rest or will turn about its axis of rotation unless compelled to change that state by an external rotational force (torque) acting upon it
117
How can Newton’s second law be made applicable to angular motion
The rate of change of angular momentum (acceleration) of a body is proportional to the force (torque) causing it and the change that takes place in the direction which the force (torque) acts
118
How can Newton’s third law be made applicable to angular motion
When a force (torque) is applied by one body to another, the second body will exert an equal and opposite force (torque) on the other body
119
How do you calculate angular momentum
Angular momentum = moment of inertia x angular velocity
120
What is moment of inertia
The resistance of a body to change its state of angular motion or rotation
121
How could Newton’s first law in relation to angular motion be shown
Ice skater spinning, They will continue to spin until they land on the ice when an external force (torque) is exerted from the ice on their skates which changes their state of motion
122
What factors affect moment of inertia
- Mass
- distribution of mass from The axis
123
How does mass affect moment of inertia
The greater the mass, the greater the moment of inertia
124
How does the distribution of mass affect the moment of inertia
The further the distribution of mass from the axis the greater the moment of inertia
125
How is moment of inertia calculated
Moment of inertia (kg/m2) = mass x distribution from the axis
126
How are angular velocity and momentum of inertia related to
- If the moment of inertia is low angular velocity is high
- If the moment of inertia is high angular velocity will be low
127
What is angular displacement
This is the smallest change in angle between the starting and finishing point. Measured in radians.
128
How many degrees is one radian
57.3 degrees
129
What is angular velocity
Refers to the rotational speed of an object and the axis about which the object is rotating. Measured in rads/s
130
How do you calculate angular velocity
Angular velocity (rads/s) = Angular displacement (rad)/ time taken (s)
131
What is angular acceleration
This is the rate of change of angular velocity. Measured rad/s2
132
How do you calculate angular acceleration
Angular acceleration (rad/s2) = change in velocity (rads/s) / time taken (s)
133
What is the conservation of angular momentum
If the mass moves closer to the axis of rotation, moment of inertia increases/decreases and angular velocity increases/decreases because angular momentum is conserved
(If one increases, the other decreases. Both cannot increase at the same time, only one)
134
What is projectile motion
Refers to the movement of an object that has been thrown, hit, kicked etc. or the human body as it travels through the air
135
What factors affect the horizontal displacement of a projectile
- angle of release
- velocity of release
- height of release
136
When the release height and landing height are the same…
The optimum release angle is 45°
137
When the release height is greater/higher than the landing height…..
The optimum release angle is less then 45°
138
When the release height is below the landing height….
The optimum release angle is more than 45°
139
Which sport has the same release and landing heights
Long jump
140
Which sport has the release height lower than the landing height
Basketball
141
Which sport has the release height higher than the landing height
Cricket, shot put, tennis etc.
142
How does the velocity of release affect the horizontal displacement of the projectile
An increase in velocity will increase horizontal displacement
143
How does the height of release affect the horizontal displacement
An increase in the release height will increase horizontal displacement due to the force of gravity constantly acting on the object
144
What two forces affect the flight path of projectiles
Weight
Air resistance
145
Weight and air resistance are crucial in deciding whether an object has a….
- True parabola (uniform curve/symmetrical) e.g. shot put
- distorted parabola (deviates from true parabola) e.g. shuttlecock
146
The longer the flight path…
The longer the air resistance can affect a projectile
147
The lighter the mass of the object….
The more susceptible it is to air resistance
148
What is fluid mechanics
The study of objects or humans that travels through liquid or gases
149
What is dynamic fluid forces
Forces such as drag or lift, concerned with the movement if liquid or gas
150
What sports does fluid dynamics have effects on
Cycling, swimming, f1, sprinting, discus, javelin
151
What is drag
Drag is a resistance force caused by a body travelling through a fluid. Drag acts in opposition to the direction of motion and has a negative effect on velocity.
152
What are the two types of drag
- Form
- surface
153
What is surface drag
Friction between the surface and the fluid environment
154
Who do swimmers overcome drag
- Shave off body hair
- skin tight suits and caps
155
What is form drag
The impact of the fluid environment on an object
156
What is streamlining
Shaping a body so it can move through fluid effectively and quickly enabling air to flow smoothly and reducing drag
157
What is turbulent flow
Flow in which the fluid undergoes irregular fluctuations in magnitude and direction
158
What is laminar flow
Layers of fluid slide smoothly over one another. They undertake smooth paths or layers and are less resistant to movement
159
What factors affect drag
- velocity of the moving body
- the cross sectional area of the moving body
- shape and surface of the moving body
160
How does the velocity of a moving body affect drag
The greater the velocity of a body through a fluid, the greater the drag.
161
How is the equipment used in velodrome cycling made to reduce drag
- helmet designed to increase laminar flow
- skin tight clothing
- Carbon fibre frame, light and streamlined disc brakes and other aero features
162
How do cyclists and speed skiers reduce drag by decreasing their frontal cross sectional area
The skiers cyclists will crouch and elbows tucked
163
How does the shape and surface of the body affect drag
You want a stremalined shape and a smooth surface. This is so that the body can promote laminar flow rather than turbulent flow.
164
What is the Bernoulli principle
The theory that an increase in speed of a fluid occurs as a result of a decrease in pressure
165
What is lift force
The force that causes a body to move perpendicular to the direction of travel
166
What is the airfoil shape
The shape of a streamlined body which is capable of generating more lift than drag
167
How is lift force achieved
For air that travels above the shape/surface: Air travels further over the top. This creates high velocity and low pressure
For air that travels below the shape/surface: Air has less distance to travel underneath. This creates low velocity and high pressure
