Flashcards in Biomechanics Years 1 & 2 Deck (85):

1

## Define Newton's 1st Law

### A body continues in a state of rest or moving with constant velocity in a straight line, unless acted upon by an external force.

2

## Define Newton's 2nd Law

### When a force acts on an object, the rate of change of momentum experienced by the object is proportional to the size of the force and takes place in the direction in which the force acts.

3

## Define Newton's 3rd Law

### For every action, there is an equal and opposite reaction.

4

## Define Velocity

### The rate of change in displacement

5

## How do you calculate velocity?

### Velocity (m/s) = Displacement (m)/Time taken (s)

6

## Define Momentum

### The quantity of motion possessed by a moving body

7

## How do you calculate momentum?

### Momentum (kgm/s) = mass (kg) x velocity (m/s)

8

## Define Acceleration

### The rate of change of velocity

9

## How do you calculate acceleration?

### Acceleration (m/s/s) = Final velocity - initial velocity / time taken

10

## How do you define centre of mass?

### The point where the mass of the body tends to be concentrated and balanced in all directions

11

## What factors affect stability?

###
- The mass of the body

- Size of the base of support

- Height of the centre of mass

- No. of points in contact with the surface

- Proximity of the line of gravity to the centre of the base of support

12

## What is the line of gravity?

### An imaginary line which extends from the centre of mass directly to the ground

13

## How can you increase stability?

###
- Increase mass of the body/ object

- Increase the size of the base of support

- Lower of the centre of mass

- Increase the number of points in contact with the surface

- Bring the line of gravity inside the base of support

14

## How do you calculate force?

###
Force (N) = Mass x Acceleration (F=Ma)

15

## Define Force

### A push or pull that alters the state of motion of a body. (N)

16

## What is Net Force?

###
The overall force acting on a body when all individual

forces have been considered

17

## What is a balanced force?

### Balanced Forces: When two or more forces acting on a body are equal in size but opposite in direction. – Net Force is ZERO.

18

## What is an unbalanced force?

### When force acting in one direction on a body is greater in size than force acting in the opposite direction. – Resulting in Net Force

19

## Name two vertical forces?

### Weight & Reaction Force

20

## Name two horizontal forces?

### Friction & Air Resistance

21

## Define friction

### The force that opposes the motion of two surfaces in contact. (N)

22

## Identify 4 factors that impact upon friction

###
Roughness or smoothness of footwear or object in contact with the ground.

Roughness or smoothness of the ground or court.

Size of the down force

Temperature of Surface

23

## Identify 4 factors that impact upon air resistance

###
- Shape of object

- Speed/velocity of release

- Frontal cross sectional area

- Smoothness of surface

24

## What are the 3 components of a lever?

### Fulcrum, Effort, Load

25

## What is the fulcrum?

### Fixed point of rotation about which the lever moves.

26

## What is the load?

### The resistance or weight to be moved. The weight of a human body part to be moved is the load.

27

## What is the effort?

### The force being applied that causes the lever to move. The agonist muscle in the human body.

28

## What is the load arm?

### The perpendicular distance from the fulcrum to the load.

29

## What is the effort arm?

### The perpendicular distance from the fulcrum to the effort.

30

## What is the tip to remember the class of lever?

### 1-2-3 F-L-E. A lever is classified by which component is in the middle of the other two components.

31

## Give 2 examples of a 1st class lever.

### The head (atlas joint) & triceps brachii (elbow joint)

32

## Give an example of a 2nd class lever.

### The ankle (phalanges & metatarsals)

33

## Give an example of a 3rd class lever.

### Biceps brachii (elbow joint)

34

## Which levers generate more force? Long or short?

### Long

35

## Which lever has a mechanical advantage?

### 2nd class due to the greater length of the effort arm in comparison to the load arm

36

## What can force plates measure?

###
Force-Time

Acceleration-Time

Velocity-Time

Displacement-Time

Force-Displacement

Motion-Gait

Impulse

37

## What is linear motion?

### Linear motion is movement of a body in a straight or curved line, where all parts move the same distance, in the same direction, over the same time.

38

## How is linear motion created?

### Linear motion results from a direct force being applied to a body, directly to the centre of mass.

39

## Define distance

### The total length of the path/ route covered from start to finish (not necessarily straight line)

40

## Define displacement

### The shortest straight-line route from start to finish

41

## Define speed

### The rate of change in distance (m/s)

42

## What is deceleration?

### When the rate of change of velocity is negative or there is a decrease in velocity over time

43

## What is angular motion?

### Angular motion results from an eccentric force being applied to a body, OUTSIDE of the centre of mass (known as torque)

44

## Name the three axis of rotation.

### Longitudinal, Transverse, Frontal.

45

## What is angular motion measured in?

### Radians - rad/s

46

## What are the three components of angular motion?

### Angular Velocity, Moment of Inertia, Angular Momentum.

47

## How do you calculate Angular Momentum?

### Angular Momentum = Angular Velocity x Moment of Inertia

48

## Define Angular Momentum

### The quantity of ANGULAR motion possessed by a moving body (kgm2)

49

## Define Angular Velocity

###
The rate of change in angular displacement OR

the rate of rotation (rad/s)

50

## How do you calculate Angular Velocity?

### Angular velocity (rad/s) = angular displacement (rad)/time taken (s)

51

## Define Moment of Inertia (MI)

### Moment of Inertia is the resistance of a body to change its state of angular motion or rotation (kgm2)

52

## How do you calculate Moment of Inertia (MI)?

###
Moment of Inertia (kgm2) = Sum of (∑)

(Mass (kg) x Distribution of Mass from Axis of Rotation(m2))

MI = ∑m x r2

REMEMBER YOU ONLY NEED TO LEARN THIS EQUATION

53

## What are the two factors affecting Moment of Inertia?

### Mass & Distribution from the Axis of Rotation

54

## How do you generate angular momentum?

### Applying Torque - Applying an eccentric force (outside the axis of rotation)

55

## What is the Conservation of Angular Momentum?

### A rotating body will continue to turn about its axis of rotation with constant angular momentum unless acted upon by an eccentric force or external torque.

56

## Once angular momentum has been generated, what happens if MI increases?

### Angular velocity decreases

57

## Once angular momentum has been generated, what happens if MI decreases?

### Angular velocity increases

58

## How does air resistance differ to drag?

### Drag is the fluid resistance encountered in water

59

## What is projectile motion?

### The movement of a body through the air following a curved flight path under the force of gravity

60

## Horizontal distance following projectile motion is affected by 4 factors. Name them.

###
Speed of release

Angle of release

Height of release

Aerodynamics (Bernoulli & Magnus)

61

## What is the optimal angle to maximise horizontal distance if release height and landing height are equal?

### 45 degrees

62

## What is a positive release height?

### If the release height is above the landing height.

63

## What is a negative release height?

### If the release height is below the landing height.

64

## If there is a negative release height, what happens to the optimum angle of release?

### It increases above 45 degrees.

65

## What is a parabolic flight path?

### When a projectile is unaffected by air resistance and follows a uniform curve, symmetrical at it's highest point.

66

## When will a projectile have a parabolic flight path?

### When weight is the dominant force (eg. shot put).

67

## What is a non-parabolic flight path?

### When a projectile is affected by air resistance. The flight path is therefore asymmetrical about its highest point as a result (Eg. shuttlecock).

68

## On a free body diagram for a projectile, which 3 labels should be shown?

### Direction of motion/Air Resistance/Weight

69

## On a resultant forces parallelogram, which 4 labels should be shown?

### Direction of motion/Air Resistance/Weight/RESULTANT FORCE

70

## Using a resultant force label on a resultant forces parallelogram, how do you determine the dominant force?

### The line the resultant force arrow is closest to shows the result force (either Air Resistance or Weight)

71

## What is the Bernoulli Principle?

### An additional force can be created by a pressure gradient as a result of differing air velocities.

72

## If air moves at high velocity is the air pressure high or low?

### LOW

73

## If air moves at low velocity is the air pressure high or low?

### HIGH

74

## What 'A' is the name of the object that is required to apply the Bernoulli Principle in sport.

### Aerofoil

75

## What is the optimal 'angle of attack' when attempting to create an aerofoil eg. when throwing a discus?

### 17 degrees

76

## What do you need, to create downward force through the Bernoulli principle?

### An inverted aerofoil

77

## Does the air travel at a greater velocity over the top or underneath a formula 1 car?

### Over the top.

78

## What two parts of a formula 1 car, funnel the air at a high velocity underneath the car?

### Front wing & spoiler

79

## Is the air pressure greater underneath or on the top of a formula 1 car?

### On the top

80

## What is the magnus effect?

###
Applying spin, eccentric force outside the COM (magnus force), to a projectile will create greater air resistance in a particular direction. This decreases air velocity, increasing pressure on this side.

81

## When air flows lines are wider, do the show higher or lower air pressure?

### HIGHER

82

## When air flow lines are narrower, do they show higher or lower air pressure?

### LOWER

83

## When air flow lines are wider, is air velocity high or low?

### LOW

84

## When air flow lines are narrower, is air velocity high or low?

### HIGH

85