Biomechanics Flashcards

1
Q

What is Newton’s first law?

A

The law of inertia
Body continues at rest or constant velocity unless acted upon by a force

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2
Q

What is Newton’s second law?

A

The law of acceleration
When a force acts on object, rate of change of momentum experienced by object is proportionate to size of the force and takes place in direction force acts

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3
Q

What is Newton’s third Law?

A

For every action there is an equal and opposite reaction

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4
Q

What is linear motion? What is it caused by? Give examples

A

Movement of a body in a straight or curved line where all parts are moving in the same distance in the same direction over the same time.
Caused by direct force
E.G 100m Sprint/Swimmer

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5
Q

What is angular motion?What is it caused by? Give Examples

A

Movement of a body part in a circular path about an axis of rotation
Caused by an eccentric force (Outside centre of mass)
E.G Shoulder during cricket bowl, hip join kicking football

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6
Q

What is general motion? Give Examples

A

Combination of linear and angular motion
E.G Swimming, running,cycling

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7
Q

What is velocity? Give equation

A

Rate of change in displacement
Displacement/Time taken

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8
Q

What is acceleration? Give equation

A

Rate of Change in Velocity
(Final velocity-Initial Velocity)/Time taken

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9
Q

What is momentum? Give Equation

A

Quantity of motion possessed by a moving body
Mass x Velocity

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10
Q

Give Ways to increase Acceleration

A

Increase Force/Velocity/Speed
Increase Friction
Reduce Mass/Weight
Improve Technique
Decrease Air Resistance

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11
Q

Define Center of Mass (COM)

A

Point where mass of body tends to be concentrated and balanced in all directions

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12
Q

Where is COM in an item in which weight is evenly distributed?

A

The Middle

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13
Q

What 3 factors does the position of the COM depend on?

A

Body’s Position
Athletes body itself (Shape)
Gender

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14
Q

When might it be useful to move COM outside the body?

A

High Jump/ Fosbury Flop

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15
Q

Define Stability

A

The ability of the body to resist motion

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16
Q

Give Factors Affecting Stability

A

Mass Of Body
Size of base of support
Height of Centre of Mass
No of Points in contact with surface
Proximity of Line of gravity to centre of base of support

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17
Q

What is the line of gravity

A

Imaginary line extending from COM directly to ground

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18
Q

What 5 things can force do?

A

Create Motion
Accelerate a body
Decelerate a body
Change direction of a body
Change Shape of body

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19
Q

What is net force?

A

The overall force acting on a body

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20
Q

When are forces balanced?

A

When net force on the body = 0

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21
Q

When are forces Unbalanced?

A

When opposite forces acting on the body are unequal in size

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22
Q

What are two vertical forces?

A

Weight and Reaction Force

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23
Q

What are two Horizontal Forces?

A

Friction and Air resistance

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24
Q

What is friction?

A

The force that opposes the motion of 2 forces in contact

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25
Q

What is reaction force?

A

When there is a point of contact between two bodies there will always be a reactionary force

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26
Q

What is sliding friction?

A

When 2 surfaces have tendency to slide over one another

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27
Q

What is Directional Friction?

A

Acts in opposite direction to motion

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28
Q

What is parallel Friction?

A

Friction acts as parallel to the two surfaces in contact with each other

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29
Q

What factors affect friction?

A

Roughness/ Smoothness of surface
Roughness/Smoothness of footwear/object in contact with ground
Size of downforce
Temperature of surface (Dependent on characteristics of body in contact)

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30
Q

What is Air resistance?

A

Force that opposes motion of a body moving through the air

31
Q

What factors affect air resistance?

A

Shape of object (Size of cross sectional areas)
Speed/Velocity of body
Frontal Cross- Sectional Areas
Smoothness of Surface

32
Q

What is the fulcrum?

A

Fixed point of rotation around which the lever moves

33
Q

What is the effort?

A

Force being applied that causes lever to move

34
Q

What is the load?

A

Resistance/Weight being moved

35
Q

What is the load arm?

A

The perpendicular distance between the fulcrum and the load

36
Q

What is the effort arm?

A

The perpendicular distance between the fulcrum and the effort

37
Q

Give examples of 1st Class levers in the body

A

Elbow (During extension)
Joint between atlas and skull

38
Q

Give examples of 2nd Class levers in the body

A

Ankle during plantar flexion

39
Q

Give examples of 3rd Class levers in the body

A

Elbow (During Flexion)
Ankle (During Plantar Flexion)

39
Q

What is mechanical efficiency referring to?

A

The distance between the effort/Load and the fulcrum.
Greater the distance, the greater the advantage/disadvantage

40
Q

What is mechanical advantage?

A

Effort Arm / Load Arm
A small amount of effort being needed to move a large load

41
Q

What class levers have a high mechanical advantage?

A

2nd Class levers

42
Q

What class levers have highest mechanical disadvantage

A

3rd Class

43
Q

What are limb kinematics used for? Give sporting examples

A

To study motion limbs and movements
E.g Golf swing, Gait, Running Technique

44
Q

Give positives of Limb Kinematics

A

Improves Technique
Improves posture/ Joint Alignment
Helps with Injury rehab

45
Q

Give negatives of limb Kinematics

A

Accessibility
Cost
Requires specialist training to use/interpret data

46
Q

What are forced plates used for?

A

Detect Ground reaction forces

To calculate:
- Force Time - Acceleration Force
- Velocity Time - Displacement Time
- Force Displacement - Impulse

47
Q

What sports are force plates used to help?

A

Swimming Starts/Turns
Jumping movements

48
Q

What are general purposes of force plates?

A

Analyse gait/walking/running
Analyse Posture
Measure/Improve Balance
Rehab/Prevent Injuries
Measure force/power/acceleration
Adapt and design prosthesis

49
Q

Give positives of using force plates

A

Injury Prevention
Rehab
Large amounts of data to analyse
Immediately available and accurate

50
Q

Give Negatives of force plates

A

Not available to most
Must be maintained and calibrated
Requires specialist training to interpret data

51
Q

What are Wind Tunnels used for? Give sporting examples

A

Used to stimulate air resistance
Cycling/F1

52
Q

Give positives of using wind tunnels

A

Improve technique
Improve design of equipment

53
Q

Give negatives of wind tunnels

A

Requires specialist training to interpret data
Not available to most people
Must be maintained/calibrated

54
Q

The movements of liquids and gases and how forces affect them.

A

Fluid mechanics/dynamics

55
Q

A force that acts in opposite to motion

A

Drag force

56
Q

Causes a body to move perpendicular to the direction of travel

A

Lift force

57
Q

Shaping the body so it can move quicker through a fluid.

A

Streamlining

58
Q

The tilt of a projectile relative to the air flow

A

Angle of attack

59
Q

Where air molecules exert less pressure the faster they travel and more pressure when they travel slower.

A

Bernoulli’s principle (cyclist helmet)

60
Q

The flow of air around a projectile that changes the speed and direction of an object.
Wind in-front- headwind.
Wind behind- tailwind.

A

Aerodynamics

61
Q

It is a frictional force which occurs when air passes over the surface of objects.

A

Air Resistance

62
Q

What does air that travel fast have?

A

Low Pressure

63
Q

What does air that travel slow have?

A

High Pressure

64
Q

What does the angle of attack do?

A
  • It changes the flow of air around the discuss so the air travels over the top of the discuss has to travel a longer distance than the air underneath
65
Q

What does a lower pressure above the dicus create?

A

The lower pressure above the dicus creates an upward lift force and allows the dicus to stay in the air for longer, resulting in a greater horizontal distance

66
Q

What happens if the angle of attack is too great?

A

Then the lift is reduced and drag increases, causing the discus to stall

67
Q

What do F1 cars have causing a downward lift force?

A

Spoilers angled so that the lift force can act in a downward direction to push the car into the track

68
Q

How do spoilers create a downward lift force?

A

Because the air that travels over the top of the car travels a shorter distance than the air underneath, due to the angle of the spoiler

69
Q

How do cyclists’ body positions benefit them?

A

Because it means that air that travels over the top of the cyclist has to travel a shorter distance than the air underneath

70
Q

What does the air travelling over a shorter distance over the top of a cyclist result in?

A

The air above the cyclist travelling at a slower velocity which therefore creates a higher pressure

71
Q

What does a higher pressure above the cyclist create?

A

A downward lift force and allows the tyres of the bike to maintain a firm grip on the track

72
Q

How does a downward lift force benefit speed skiers?

A

Because more downward acting lift means more force which melts the snow for a better friction-free surface