Biomechanics Flashcards
1
Q
What is the difference between quantitative and qualitative analysis?
A
Quantitative looks at the numerical data whereas qualitative is the quality of the performance
2
Q
What is quantitative analysis based on?
A
Measurement of kinetic (force) and kinematic (distance, speed, acceleration) variables
3
Q
What is goniometry?
A
The measurement of joint angles
4
Q
What is electromyography?
A
Records the electrical activity within a muscle just prior to contraction
5
Q
What is force defined as?
A
A push or pull
6
Q
In what ways can forces affect objects?
A
- change shape of object
- move the object
7
Q
How can force be calculated?
A
Mass x acceleration
8
Q
What is gravity?
A
A constant force that acts through the centre of mass of an object towards the earth
9
Q
What is friction?
A
Occurs when two surfaces come in contact with each other
10
Q
What is drag force?
A
When an object moves trough air or water
11
Q
What is mass?
A
The measure of the amount of matter na object is mad duo of
12
Q
What are the units for mass?
A
Kilograms
13
Q
What does weight refer to?
A
The force that is exerted on the body by gravity.
14
Q
How can weight be determined?
A
Mass x gravity
15
Q
What are the units for weight?
A
Newton’s
16
Q
Is inertia?
A
The tendency for a body to resist a change in its state of motion
17
Q
Is it harder or easier to change the state of motion of an object with greater levels of inertia?
A
Harder
18
Q
What is momentum?
A
The measure of the amount of motion an object has and its resistance to changing that motion.
19
Q
What are the units for momentum?
A
Kg m/s
20
Q
What is the equation to determine the momentum of an object?
A
Mass x velocity
21
Q
What is the equation for weight?
A
Mass x gravity
22
Q
What are sporting examples of friction?
A
- chalk increases friction and therefore grip for weightlifters and gymnasts
- polished skis reduce friction and increase speed
23
Q
What are sporting example that reduce drag forces?
A
In swimming the swimsuits, caps, body position all reduce drag forces in the water to increase speed
24
Q
How much momentum does an object at rest have?
A
None
25
If an object has greater momentum is it easier or harder to stop?
Harder
26
What is velocity?
How fast something is moving in a particular direction
27
What is the equation for momentum?
Mass x velocity
28
What is the conservation of movement-linear?
Relates to the transfer of momentum during a collision
29
What is the summation of momentum?
Sequential summation of momentum from the beginning of the movement to the end
30
What does summation of momentum result in?
Maximal force production
31
What is impulse?
When the momentum of something is changed
32
What is the equation for impulse?
Force x time
33
What are some examples of impulse?
- applying a large force over a short period of time (hitting golf ball)
- applying large force over long period of time (shot put, discus)
34
What is Newton’s first law called?
The law of inertia
35
What is Newton’s first law of inertia?
A body or object will remain in motion or at rest in a straight line unless acted upon by an external force
36
What is Newton’s second law called?
Law of acceleration
37
What is Newton’s second law of acceleration?
A force applied to applied to an object will produce a change in motion (acceleration) in the direction of the applied force tat is directly proportional to the size of that force
38
What is the equation for force?
Mass x acceleration
39
What is Newton’s third law called?
The law of action reaction
40
What is Newton’s third law of action reaction?
Every action had an equal and opposite reaction
41
What are examples of Newton’s third law of action reaction?
- pushing off starting blocks
| - each footstep on ground when running
42
What is angular motion?
Any movement around an axis
43
What is a torque?
Refers to a force applied that results in angular motion
44
What is Newton’s first law of angular motion?
The angular momentum of a body remains constant unless acted upon by an external force
45
What is Newton’s second law of angular motion?
A torque applied to an object will produce change in angular motion in direction of rapplied torque, directly proportional to size of torque and inversely to the moment of inertia
46
What is Newton’s third law of angular motion?
For every torque there is an equal and opposite torque
47
What is angular momentum?
The amount of angular motion an object or body has (same as normal momentum)
48
What is the equation for angular momentum?
Moment of inertia x angular velocity
49
What is moment of inertia?
How easy or hard it is for rotation to occur.
50
If mass is closer to the axis does the moment of inertia increase or decrease?
Decrease
51
What is the angular velocity?
How fast an object or body is rotating
52
As moment of inertia increases the angular velocity...
Decreases
53
What is the conservation of angular momentum?
When a body is rotating, angular momentum is always constant(in air)
54
What is linear motion?
Movement of a body along a straight or curved path
55
How does the body move in linear motion?
All body parts move in the same direction at the same speed
56
What is the difference between speed and velocity?
Velocity takes into account the direction of movement and how fast something is travelling
57
What is the equation for acceleration?
Change in velocity divided by change in time
58
What is positive linear acceleration?
Speeding up
59
What is negative linear acceleration?
Slowing down
60
What is zero linear acceleration?
Moving at a constant velocity at a constant velocity (stationary or maintaining)
61
What is acceleration?
A change in velocity over a period of time
62
What is projectile?
An object or a body launched into the air is a projectile
63
What are the factors that affect projectiles?
-angle, speed and height of release
64
What is equilibrium?
An object is said to be in equilibrium when there are no unbalanced forces or torques acting on it
65
What is static equilibrium?
Must not be moving or rotating, all forces and torques on the body or object must be zero
66
What is an example of static equilibrium?
Sitting still on a chair not moving or a golf ball on a tee
67
What is dynamic equilibrium?
When a body or object is moving with a constant velocity
68
What is an example of dynamic equilibrium?
Walking or jogging at a steady pace
69
What is stability?
Is the resistance to the disruption of equilibrium
70
What is balance?
The ability to control equilibrium
71
When stability increases is it easier or harder to u balance?
Harder
72
What is an example of a sport that aims to reduce stability?
Swimmers use stance on blocks to decrease stability, only a small movement forward is start moving
73
What is an example of a sport that increases stability?
Wrestlers use positions that increase stability making it more difficult for their equilibrium to be disrupted
74
What is an example of a sport where control of equilibrium is essential?
Gymnasts need good balance for floor or beam routines. They must also increase stability at times such as landing a somersault
75
What is an example of a sport that requires high levels of balance to control equilibrium when stationary?
A platform diver holding a stationary position on board
76
What is an example of a sport that requires high levels of balance to control equilibrium when moving?
A hockey player must maintain balance when weaving through opponents
77
What are factors that affect stability?
- base of support
- centre of gravity
- body mass
- friction between body and surfaces
78
How does the base of support affect stability?
The larger the base of support the higher the stability
79
What is a sporting example of base of support and stability?
A baseball player has a wide stance to not lose balance when swinging
80
What is the centre of gravity?
The point around which an objects weight is balanced
81
Can the centre of gravity change?
Ye sit can change as body position changes
82
If the centre of gravity is lower does the stability increase or decrease?
Increases
83
What is the line of gravity?
The direction gravity acts on
84
When the line of gravity acts through the middle of the base of support is stability increased or decreased?
Increases
85
What is a sporting example of the line of gravity?
Rugby players or surfers bend down to get closer to their base of support to increase stability
86
How can body mass influence stability?
The greater the mass of an object or body the greater the stability
87
In what sport would increased body mass be an advantage?
Wrestling
88
In what sport would decreased mass be an advantage?
Gymnastics due to constant changing of stability
89
How can friction influence stability?
Increasing friction between the body and the surface it is in contact with increases stability
90
What is an example of friction aimed to increase stability?
Waxing a surfboard
91
What are levers?
Are simples machines that have a mechanical advantage
92
What mechanical advantage do levers allow?
- apply a small force to move cub gretare resistance
| - move one point of an object a small distance causing another point to move a large distance
93
What is the mechanical advantage of a second class lever?
More than 1 making it easier to move a large resistance
94
What is the advantage of a first class lever?
Can change depending on axis location
95
What is the mechanical advantage of a third class lever?
Less than 1, meaning more force is required but results in increased range of motion and angular speed/velocity
96
What are most types of levers in the body?
Third class
97
Does increased lever length increase or decrease the moment of inertia?
Increases
98
What is a lever comprised of?
Axis, effort and resistance force
99
What is the order for a first class lever?
Far
100
What is the order for a second class lever?
Arf
101
What is the order for a third class lever?
AFR
102
What is an example of a first class lever?
Soccer header
103
What is an example of a second class lever?
Calf raise
104
What is an example of a third class lever?
Hitting using a baseball bat
