Biomechanics 1.3a

Question 1

Newtons First Law - Inertia

Answer 1

-Body continues in a state of rest or velocity unless a force is acted upon it (unbalanced/external)

Question 2

Newtons Second Law - Acceleration

Answer 2

-Bodies rate of change of momentum is proportional to the size of force applied and acts in same direction

Question 3

Newtons Third Law - Reaction

Answer 3

-For every action there is an equal or opposite reaction

Question 4

Example of First Law - Inertia

Answer 4

• Golf ball still unless force applied

- Or Golf ball remain constant unless force

Question 5

Example of Second Law - Acceleration

Answer 5

-When Golf ball struck, rate of change of momentum is proportional to size of the force acted on by club

Question 6

Example of Third Law - Reaction

Answer 6

• Tennis player hitting ball

- racquet exerts force and ball exerts an equal and opposite force on the racquet

Question 7

Velocity

Answer 7

-Rate of change of displacement

Question 8

Velocity Equation

Answer 8

-Velocity = Displacement/Time Taken

Question 9

Momentum

Answer 9

-Quantity of motion possessed by a moving body

Question 10

Momentum Equation

Answer 10

-Momentum = mass x velocity

Question 11

Acceleration

Answer 11

-Rate of change in Velocity

Question 12

Acceleration Equation

Answer 12

-Acceleration = (FV-IV)/Time Taken

Question 13

Force

Answer 13

-A push or pull that alters the state of motion of a body

Question 14

Force Equation

Answer 14

-Force = mass x acceleration

Question 15

What are the types of force

Answer 15

• External (outside of body)

- Internal (Skeletal muscle)

Question 16

What effect can force have

Answer 16

• Create Motion
• Accelerate a body
• Decelerate a body
• Change direction of a body
• Change shape of a body

Question 17

Net Force factors

Answer 17

• If NF = 0
• No change in motion, forces balanced
• If NF present
• Change in motion, forces unbalanced

Question 18

External Forces and what are they divided into

Answer 18

• Vertical forces = Weight and Reaction

- Horizontal forces = Friction and Air resistance

Question 19

Weight force

Answer 19

• Measured in Newtion (N)

- kg x acceleration = (m/s/s)

Question 20

Weight definition

Answer 20

-gravitational pull that earth exerts on a body

Question 21

Reaction definition

Answer 21

-the equal and opposite force exerted by a body in response to the action force place above it

Question 22

Friction definition

Answer 22

-the force that opposes the motion of two surfaces in contact

Question 23

Net force definition

Answer 23

-sum off all forces acting on a body

Question 24

4 Factors effecting friction

Answer 24

• roughness of ground surface
• roughness of contact surface
• Temperature
• Size of normal reaction

Question 25

Example of roughness of ground surface (friction)

Answer 25

-Athletes run on rough rubber tracks

Question 26

Example of roughness of contact surface (friction)

Answer 26

-Athletes wear spiked shoes

Question 27

Example of Temperature (friction)

Answer 27

-Higher temperature increases friction

Question 28

Example of size of normal reaction (friction)

Answer 28

-shot putter high mass due to N 3rd Law

Question 29

Air resistance definition

Answer 29

-the force that opposes motion through air

Question 30

4 factors affecting air resistance

Answer 30

- Velocity - Shape - Front cross-sectional area - Smoothness of surface

Question 31

Streamlining

Answer 31

-creation of smooth air flow around an aerodynamic shape to minimise air resistance

Question 32

free body diagram

Answer 32

-clearly labelled sketch showing all forces acting on a body at a particular time

Question 33

Centre of Mass

Answer 33

-the point at which an object or a body is balanced in all directions, point which weight appears to act

Question 34

Stability

Answer 34

-ability of a body to resist motion and remain at rest, also ability to withstand a force applied and return to its original position without damage

Question 35

4 Factors that effect stability

Answer 35

- Mass of the body - height of COM - size of the base of support - Line of gravity

Question 36

Mass of body effect on stability

Answer 36

-greater the mass, greater inertia

Question 37

Height of COM effect on stability

Answer 37

-lower COM, greater the stability

Question 38

Size of BoS effect on stability

Answer 38

- Greater size of BOS, greater stability | - increased by many points of contact

Question 39

Line of gravity effect on stability

Answer 39

-More central line of gravity, greater the stability

Question 40

two main functions of levers

Answer 40

- generate muscular effort to overcome given load | - increase the speed of a given movement

Question 41

First Class lever system

Answer 41

- fulcrum in the middle | - E-F-L or L-F-E

Question 42

Second Class lever system

Answer 42

- Load is in the middle | - E-L-F or F-L-E

Question 43

Third Class lever system

Answer 43

- Effort is in the middle | - L-E-F or F-E-L

Question 44

Example of first class lever system

Answer 44

-Extension of the neck when heading a football

Question 45

Example of second class lever system

Answer 45

-Ball of the foot in the take-off phase of a high jump

Question 46

Example of Third class lever system

Answer 46

-Flexion of the elbow during a biceps curl

Question 47

Mechanical Advantage

Answer 47

- second class lever system where effort arm is greater than load arm. - large load can be moved with a relatively small effort

Question 48

Mechanical Disadvantage

Answer 48

- third class lever system where load arm greater then effort arm - Large effort is required to move a small load

Question 49

3 examples of technology which analyses movement

Answer 49

- Limb Kinematics - Force Plates - Wind Tunnels

Question 50

Limb Kinematics

Answer 50

-Study of movement in relation to time and speed

Question 51

Force Plates

Answer 51

-Ground reaction forces are measured in laboratory conditions

Question 52

Wind tunnels

Answer 52

-steel frame buildings containing wide fans where artificial wind is produced