Bio-mechanical Movement Flashcards
What is SURFACE DRAG ?
Relates to friction between the surface of object and fluid environment
- known as skin drag
- wear specialised/smooth clothing to reduce surface drag
How to interpret the force-time graphs ?
the area under the graph represents the impulse (change in momentum)
1) START of race (100m)
- net impulse is positive = accelerate
2) MIDDLE of race (100m)
- net impulse is zero = constant velocity
3) End of race (100m)
- net impulse is negative = de-accelerate
What is ANGULAR MOTION ?
is the movement around a fixed point
- rotation around one of the axis e.g. somersault
- force applied outside the centre of mass - eccentric force
What are the factors that affect Friction ?
1) Surface characteristics of two bodies in contact
- e.g. spikes minimise friction
2) Temperature of two surfaces in contact
- e.g. curling - hooter reduces friction
3) Mass of object sliding
- e.g. larger mass means larger friction
What is the FIRST CLASS LEVER ?
Effort -> Fulcrum -> Resistance
- e.g. elbow extension (or neck)
How does “Height of release” affect the horizontal displacement of a projectile ?
The GREATER the height of release, the GREATER the horizontal displacement
- e.g. shot put release at greatest height as weight force is constant acting on ball
What are Positive and Negative for the Second class lever ?
POSTIVE
- generate much larger forces in short distance
NEGATIVE
- limited range of movement + move slowly
How does the “Mass of the Performer” affect stability ?
The GREATER the mass, the MORE stability there is
What is HORIZONTAL DISPLACEMENT ?
is the shortest distance from the starting position to the finishing position in a line parallel to the ground
How is CONSERVATION OF MOMENTUM achieved ?
Momentum is conserved always - stays constant unless acted upon by force
- Example is when no friction - ice skater
- ice skater wants to speed up spin by manipulate their moment of inertia
1) start of spin = arms + legs out to increase moment of inertia so velocity is low
2) arms + legs in line with axis of rotation so moment of inertia decreases so angular velocity increases
What is the Centre of Mass ?
Is the point of balance of a body
- will change depending on position
What is VELOCITY ?
the rate of change of displacement
- UNITS = ms^-1
- V = Δs/Δt
What is Air Resistance and How does Air Resistance affect the performer ?
Air Resistance is the force acting in opposite direction to motion of a body travelling through the air
What is MECHANICAL DISADVANTAGE ?
Is when the resistance arm is longer than the effort arm
- EA
What is MECHANICAL ADVANTAGE ?
Is when the effort arm is longer than the resistance arm
- EA>RA
What is the ANGLE OF ATTACK ?
Is the tilt of a projectile relative to the air flow
- it changes the flow of air around the object
- if too great - lift is reduced + drag increased
What is MOMENTUM ?
the product of the mass and the velocity of the object
- UNITS = kgms^-1
- p = mv
What is FORM DRAG ?
Relates to impact of fluid environment on an object
- known as shape drag
- force affecting the leading edge of object increases form drag - STREAMLINING
What is a reaction force ?
This occurs when two bodies in contact with one another
What are the factors that affect Air Resistance ?
1) Velocity of moving object
- e.g. faster means larger resistance
2) Cross-sectional area of moving object
- e.g. larger S.A means larger resistance
3) Shape + surface characteristics of moving body
- e.g. streamlined shapes reduce resistance
How does the “Cross-sectional area of moving object” affect drag ?
The LARGER S.A, the LARGER the drag force
- e.g. cyclist crouching to reduce effect of drag
What is Fluid Mechanics ?
Is the study of fluids + how forces affect them
- Dynamic fluid concerns the movement of liquids + gases - experience drag and lift force
What are Positive and Negative for the First/Third class lever ?
POSTIVE
- larger range of movement + move quickly
NEGATIVE
- can’t apply much force to move an object
What is the Law of REACTION ?
States to every force there is an equal and opposite reaction force
- e.g. sprint start on the blocks
What is a VECTOR ?
Is Measurements of SIZE and DIRECTION
What are Newton’s Laws of Linear Motion ?
1) Law of INERTIA
2) Law of ACCELERATION
3) Law of REACTION
What are the Vector Components of Parabolic flight ?
HORIZONTAL COMPONENT - the horizontal motion of an object
VERTICAL COMPONENT - the vertical motion of an object
- start of flight - resultant force up
- end of flight - resultant force down
What are the factors which affect drag ?
1) Velocity of moving object
2) Cross-sectional area of moving object
3) Shape + Surface characteristics of moving body
What is LIFT FORCE ?
It causes a body to move perpendicular to direction of travel
- e.g. Discus thrown experiences an upward lift force
- stay in air for longer - increase horizontal displacement
What is the SECOND CLASS LEVER ?
Fulcrum -> Resistance -> Effort
- e.g. flexion at the ankle
What is STREAMLINING ?
Involves shaping a body so it can move effectively + quickly through a fluid
- e.g. swimmer making body shape thin or cyclist drafting by close behind front cyclist
What is SPEED ?
the body’s rate of change of position
- UNITS = ms^-1
- S = d/t
What are the factors which affect stability ?
1) Height of the centre of mass
2) Position of line of gravity
3) Area of base of Support
4) Mass of the Performer
What is DISPLACEMENT ?
the shortest distance in a straight line between the start and finish position
- UNITS = m
How does the Bernoulli’s Principle affect the lift force of a Discus ?
When the angle of attack of a discus is between 25-40 degrees
- air over top travels longer distance
- so air molecules above travel at a faster velocity
- causing lower pressure than below
- causing a lift force upwards
- result in greater horizontal distance
How does the “Height of the centre of mass” affect stability ?
The LOWER the height of centre of mass will INCREASE stability
What is Weight and How does Weight/Gravity affect the performer ?
Weight is the product of the mass and the acceleration the object
- force pulling body towards centre of earth
- greater mass means greater force
What is the Law of INERTIA ?
States a body will remain at rest or at a constant velocity unless acted on by an external force
- e.g. high jump changing state of motion
How does “Speed of release” affect the horizontal displacement of a projectile ?
The GREATER the velocity of projectile, the GREATER the horizontal displacement
How does “Angle of release” affect the horizontal displacement of a projectile ?
This ensures the object travels as far as possible
- optimum angle of release is dependent upon the release height + landing height
1) release height = landing height means optimum angle of release is 45 - e.g. long jump
2) release height < landing height means optimum angle of release is greater than 45 - e.g. basketball
3) release height > landing height optimum angle of release is less than 45 - e.g. shot put
What are the factors which affect the horizontal displacement of a projectile ?
1) Angle of release
2) Speed of release
3) Height of release
What is MASS ?
the quality of matter a body possesses
- UNITS = kg
What is Linear Motion ?
The motion in a straight line or curved line, with all body parts moving the same distance at the same speed in the same direction
e.g. 100/200m
What is the MOMENT OF INERTIA ?
INERTIA is a resistance to change in motion so MOMENT OF INERTIA is the resistance of a body to angular motion
- depends on mass + distribution of mass around the axis
- greater mass = greater resistance to change = greater moment of inertia
- greater distance of distributed of mass from axis = Increase moment of inertia e.g. tucked position
How does the “Area of base of Support” affect stability ?
If there is more contact points, the base will be LARGER so will be MORE stable
What is Angular Momentum ?
Moment of inertia x angular velocity
- both inversely proportional to each other
- Angular Momentum means “spin”
What is a PARABOLA ?
A curve with matching left and right hand sides
What is Angular Acceleration ?
Is the rate of change of angular velocity
- UNITS = radians/s^2
How does the “Velocity of moving object” affect drag ?
The GREATER the velocity through a fluid, the GREATER drag force
-e.g. racing cars
What is Projectile motion ?
Is movement of object/human in the air
What does a Lever consist of ?
1) FULCRUM - are the joints
2) EFFORT -provided by the muscles
3) RESISTANCE - weight being moved e.g. gravity
FRE-123
What is IMPULSE ?
FORCE x TIME
- impulse = change of momentum
- increase momentum by increasing either muscular force applied or time for force applied
- decrease momentum by increasing time so force applied is reduced - controlled landing + reduce chance of injury
What is the Law of ACCELERATION ?
States the acceleration for a body is proportional the the force causing it and takes place in the same direction
- F = MA
- e.g. athlete at sprint start
What is the THIRD CLASS LEVER ?
Fulcrum -> Effort -> Resistance
- e.g. whole body
What is Drag ? And what are the two types ?
Is a force that acts in opposition to motion
- effects velocity negatively
- produced from friction + air resistance
1) SURFACE DRAG
2) FORM DRAG
How Forces act upon a performer during Linear Motion ?
- Vector so shown using arrows as magnitude
- Net force = resultant force
- if air resistance = friction then net result is zero
- friction is longer means athlete with accelerate
What is WEIGHT ?
the gravitational forces exerted on an object
- UNITS = N
What is DISTANCE ?
the path a body takes as it moves from the starting position to the finishing position
- UNITS = m
What is Angular Velocity ?
Is the rate of change of angular displacement
- UNITS = radians/s
How does the “Position of line of gravity” affect stability ?
This should be central OVER the base of support to INCREASE stability
What is ACCELERATION ?
the rate of change of velocity
- UNITS = ms^-2
- A = Δv/Δt
How to apply Newton’s Laws to Angular motion ?
1) a rotating body will continue in it’s state of angular motion unless acted on by an external force - TORQUE - rotating force
- e.g. ice skater continue to spin in air till land
2) rate of change of angular momentum of body is proportional to the force causing it, in the same direction
- e.g. leaning forward on diving board
3) when a torque is applied by one body to another, the other body apply’s an equal but opposite torque
- e.g. hanging technique in long jump
What is a SCALAR ?
Is Measurements of only SIZE/MAGNITUDE
How does the Bernoulli’s Principle affect the lift force of a Cyclist/Sport cars ?
A lift force can work downwards - cause greater frictional force so greater grip
- shaped so angle of attack causes the air over top travels a shorter distance
- so air molecules above travel at a slower velocity
causing higher pressure than below
- maintain grip at high speed + around curves
What is Bernoulli’s Principle ?
States where air molecules exert less pressure the faster they travel + more pressure when they travel slower
- angle of attack is very important
What are the factors affecting flight path of different projectiles ?
1) Weight
2) Air Resistance
- whether is TRUE parabola or DISTORTED parabola
- larger weight force + small air resistance = true parabola e.g. shot put
- light wight force + greater air resistance = distorted parabola e.g. shuttlecock
- longer flight path, greater effect of air resistance
What Forces act upon a performer during Linear Motion ?
INTERNAL - is generated by the skeletal muscles EXTERNAL - comes from outside the body - weight/gravity - reaction - Friction - Air Resistance
What is Friction and How does Friction affect the performer ?
Friction occurs when two or more bodies are in contact with one another - acts in opposite to motion
- there are two types ; static + sliding
1) STATIC - occurs before an object starts to slide
2) SLIDING - occurs when surfaces are moving relative to one another
What is Angular Displacement ?
Is the smallest change in angle between the starting and finishing position
- UNITS = radians
How does the “Shape + Surface characteristics of moving body” affect drag ?
The more Streamlined/aerodynamic shape will reduce drag force
- sport scientists research to try get marginal gains in speed
- e.g. cyclist air dust gaps to reduce drag or speed skier helmet extend to shoulder
