Biomechanical Principles, external factors and free body diagrams Flashcards Preview

A-Level PE Anatomy And Physiology > Biomechanical Principles, external factors and free body diagrams > Flashcards

Flashcards in Biomechanical Principles, external factors and free body diagrams Deck (34)
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1

What are Newton’s three laws

1st law - law of inertia
2nd law - law of acceleration
3rd law - law of reaction

2

Define Newton’s first law of inertia

A body will remain in a state of rest or uniform velocity unless acted on by an external or unbalanced force

3

Define Newton’s second law of acceleration

The acceleration of a body is proportional to the size of the force applied and takes place in the direction at which the force acts

4

Define Newton’s third law of reaction

For every action there is an equal and opposite reaction. The reaction force is equal in size and opposite in direction to the action force

5

Give a sporting example of Newton’s first law of inertia

A football will remain at rest on the penalty spot until a force is applied to the ball by the players foot

6

Give a sporting example of Newton’s second law of acceleration

The acceleration of a netball during a pass is proportional to the force from the muscle and is in the same direction of the force

7

Name a sporting example of Newton’s third law of reaction

When serving, a tennis player pushes downwards on the ground (action force) and the ground pushes upward on the player (reaction force)

8

Define force

Force is a push or pull that tends to alter the state of motion of the body

9

Define balanced forces

When two or more forces acting on the body are equal in size and in opposite directions they cancel out

10

Define unbalanced force

When two or more forces acting on the body do not cancel out so a net force acts upon the body

11

Define net force

Also known as the resultant force, this is the overall force acting on a body when all forces are considered

12

Where do external forces originate from

Outside the body

13

What are the 4 external forces

Weight, reaction, friction and air resistance

14

Define weight

The force that acts directly downwards from the centre of mass

15

Define reaction

Reaction force acts upwards from the point(s) of contact with the ground in reaction to all forces

16

Define friction

Friction opposes the sliding motion of one surface across another

17

Define air resistance

Air resistance acts against the direction of motion opposing the movement of the body through the air

18

What are the 4 factors effecting friction

1. Characteristics/roughness of surface 1 (sole of footwear)
2. Characteristics/roughness of surface 2 (playing surface)
3. Force/normal ground reaction force (the force pushing the two surfaces together)
4. Temperature (heated tyres increase friction)

19

State 3 ways in which friction can be maximised

1. Increase the roughness of surfaces
2. Increase the mass/downforce (heavy props)
3. Increase the temperature of materials

20

State one way in which you can minimise friction

Increase the smoothness of surfaces

21

State the 4 factors that effect air resistance

1. Velocity of person/object
2. Frontal cross section of object
3. Streamline/shape of object
4. Surface characteristics

22

State three ways in which air resistance can be minimised

1. Reduce the frontal cross sectional area
2. Using a streamline shape
3. Making surfaces smoother

23

Where does weight originate from

Centre of mass

24

Which direction does weight act upon

Vertically downwards

25

How long is the arrow for weight

Proportional to the objects mass

26

Where does reaction originate from

All points of contact with the ground

27

Which direction do reaction forces act

Upwards perpendicular to the ground

28

How long are the arrows representing reaction

Equal but opposite to all downwards acting forces

29

Where does air resistance originate from

Centre of mass

30

Which direction does air resistance act

Opposite to the direction of motion

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