Biomechanics

Question 1

Momentum

Answer 1

Mass x velocity
Amount of motion an object posesses

Question 2

How can momentum be increased?

Answer 2

• Increase speed
• Increase mass

Question 3

Law of conservation momentum

Answer 3

Momentum is conserved in any interaction with a closed system (a system that does not lose or gain mass, or isn’t affected by external factors)

Question 4

Impulse

Answer 4

Force x time
A change in momentum, result of a force acting on an object over a period of time

Question 5

Methods to increase impulse

Answer 5

Apply a greater force
Apply the force over a greater period of time

Question 6

Elasticity

Answer 6

The degree of compression then expansion of an object to its original shape

Question 7

Coefficient of Restitution

Answer 7

The bounciness of an object, measures the elasticity of a collision, and the remaining energy after a collision.
- when a COR = 1 it is a perfectly elastic collision
- when a COR = 0 it is a perfectly inelastic collision

Question 8

Factors that influence the coefficient of restitution

Answer 8

Temperature
Velocity
Equipment
Surfaces

Question 9

Equation of COR

Answer 9

square - height of rebround/height of drop

Question 10

3rd Class Levers

Answer 10

Fulcrum, Effort, Load
Speed Increaser

Question 11

Moment of Inertia

Answer 11

resistance to rotational motion

Question 12

Angular Momentum

Answer 12

angular velocity x moment of inertia
refers to the quantity of angular motion possesed by a rotating body.

Question 13

Angular Velocity

Answer 13

rate of change in angular position of a body

Question 14

Drag

Answer 14

Horizontal

Question 15

Lift

Answer 15

Vertical

Question 16

Turbulent Flow

Answer 16

velocity which at any point varies erratically

Question 17

Laminar Flow

Answer 17

Fluid moves smoothly in individual streams and layers

Question 18

Boundary Layer

Answer 18

thin layer of air surrounding of attached to an object

Question 19

Factors that affect Boundary Layer Seperation

Answer 19

Velocity
-low: boundary layer clings to the surface, seperation is pushed well to the back (reducing drag)
-high: seperation is pushed further forward (increasing drag)
Surface Roughness
- rougher surfaces create turbulent layers, reducing drag e.g. Golf Ball
Shape
-Oval: seperation well to the rear (reducing drag)
-Shape: seperation is further forward (increasing drag)

Question 20

Surface Drag

Answer 20

Friction created between a fluid and the surface of a moving object
Factors affecting:
- Relative velocity
-Relative roughness
- Surface area of the object
- Viscosity of the fluid

Question 21

Pressure Drag

Answer 21

Resistance created by a pressure differential between the front and back of an object moving through fluid.
Factors affecting:
-Cross sectional area of the object
- Velocity of the object
- Surface roughness
-Shape

Question 22

Wave Drag

Answer 22

Creation of waves at the point where air and water interact cauisng resistance to motion
Factors Affecting:
- Relative wave velocity
-Technqiue
-Open vs CLosed water

Question 23

Slipstream

Answer 23

An area of reduced air pressure and forward suction behind a moving object

Question 24

Ways to increase balance

Answer 24

Lower centre of gravity
Increase width of base of support
Centralise line of gravity
Increase Mass
Increase number of contact points with the ground

Question 25

Balance

Answer 25

the ability to neutralise forces that distrub equilibrium or the ability to maintain/hold a position

Question 26

Sports that recquire less balance

Answer 26

Diving, sprinting, taking off

Question 27

Sports that recquire more balance

Answer 27

Sumo wrestling, weightliting

Question 28

Segmental Interaction

Answer 28

forces acting between the segments of a body can transfer energy between them or how body segments interact with one another to meet the task's demands

Question 29

Power

Answer 29

More segments used, sequentially summated

Question 30

Accuracy

Answer 30

Less segments used, simultaneously summated

Question 31

Simultaneous Movement

Answer 31

All body parts move at the same time to produce a force and accuracy.

Question 32

Sequential Movement

Answer 32

Combination of forces produced by different body parts acting together producing maximum force.

Question 33

Principles of effective sequential movement

Answer 33

1. Move stronger and larger muscles first followed by smaller and faster muscles 2. Sequentially accelerate to ensure that optimum momentum is passed from one body part to the next 3. Ensure that each body part is stable 4. Use as many body parts as possible 5. Follow through to avoid deceleration 6. All forces are directed towards the target.

Question 34

Optimal Projection

Answer 34

the angle at which a projectile must travel in order to maximise distance

Question 35

Ways to maximise distance

Answer 35

Maximise velocity Maximise height of release Angle of release

Question 36

Bernoulli's principle

Answer 36

Relates to pressure created by a moving fluid over an object, whereby fast moving fluid creates a low pressure area, and slow moving fluid creates a high pressure area.

Question 37

Magnus Effect

Answer 37

Force that acts perpendicular to the forward path of moving objects