PAPER 1 > BIOMECHANICS Flashcards
NEWTON’S FIRST LAW
[ INERTIA ]
a body continues at a state of rest or uniform velocity unless acted upon by an external source or unbalanced force
NEWTON’S SECOND LAW
the acceleration of a body is proportional to the force causing it and the acceleration takes place in the direction in which the force acts
NEWTON’S THIRD LAW
every action has an equal and opposite reaction
NEWTON’S FIRST LAW EXAMPLE
a rugby ball continues in a state of rest on the kicking tee until acted upon by the external source / force of Dan Carters boot
NEWTON’S SECOND LAW EXAMPLE
the acceleration of the bobsleigh is proportional to the force applied by the bobsleigh athletes and the bobsleigh accelerates in the direction which the athletes applied force to it
NEWTON’S THIRD LAW EXAMPLE
as the gymnast applies force to the beam, the beam applies an equal and opposite force to the gymnasts hands allowing her to do a back walk over
VELOCITY
the rate of change in displacement (movement) and this is a term used and closely related to speed, acceleration and time
VELOCITY EQUATION
velocity = displacement ÷ time taken
ACCELERATION
the rate change in velocity
ACCELERATION EQUATION
acceleration = (final velocity - initial velocity) ÷ time taken
MOMENTUM
the quantity of motion possessed by a moving body
MOMENTUM EQUATION
momentum = mass x velocity
FORCE
a push or pull action that alters the state of motion of a body
FORCE EQUATION
force = mass x acceleration
FRICTION
[ 4 MAIN FACTORS ]
> roughness of the ground surface
roughness of the contact surface
temperature
size of normal force (mass + acceleration)
FREE BODY DIAGRAMS
> direction of movement > air resistance > weight > reaction > friction > vertical forces > horizontal forces
VERTICAL FORCES
balanced - no movement
> weight
> reaction
HORIZONTAL FORCES
unbalanced - movement
> direction of movement
> friction
> air resistance
BIOMECHANICAL LEVERS
[ DIFFERENT PARTS ]
> fulcrum > load > effort > load arm > effort arm
MECHANICAL ADVANTAGE
EA > LA
> easy to lift
MECHANICAL DISADVANTAGE
LA > EA
> difficult to lift
BIOMECHANICS ANAGRAM
1 2 3
F L E
1ST CLASS
E F L
2ND CLASS
F L E
3RD CLASS
F E L
CENTRE OF MASS
the point in which a body is balanced in all directions
BASES OF SUPPORT
the point / points where the body is in contact with the surface that the body is resting on
LINE OF GRAVITY
a line extending from the centre of mass vertically down to the ground
TO IMPROVE STABILITY
[ CENTRE OF MASS ]
become lower to the ground to improve stability
TO IMPROVE STABILITY
[ BASES OF SUPPORT ]
widen their bases of support or if possible to be able to add more bases of support to improve stability
TO IMPROVE STABILITY
[ LINE OF GRAVITY ]
maintain their line of gravity straight to the floor and central to improve stability
LIMB KINAMATICS
study the movement and relationship between time and space
> 3D or optional motion analysis records of sporting actions or normal bodily movements
> joint and limb efficiency
> bone geometry / displacement / velocity / acceleration
WHAT DO LIMB KINAMATICS DO
record / capture / convert the motion shown by reflective markers
WHERE ARE LIMB KINAMATICS POSITIONED ON THE BODY
placed on body joints and bony landmarks
USED ON WHAT SKILL TYPES
golf swing / football kick
LIMB KINAMATICS ADVANTAGES
> accurate
prevents injury
improves technique
LIMB KINAMATICS DISADVANTAGES
> requires accuracy in positioning > do not cater for specific individuals > expensive > highly specialised > largely limited > lab conditions
FORCE PLATES
ground reaction forces
WHAT DO FORCE PLATES DO / WHERE ARE THEY USED
measures the ground reaction forces
> measured in laboratory conditions
WHAT ARE FORCE PLATES
measures size of force and time the force is applied
WIND TUNNELS TEST
they test for aerodynamic efficiency
FUNCTION OF WIND TUNNELS
object is placed inside the wind tunnel and instruments are used to measure the forces produced
WHAT IS INJECTED INTO WIND TUNNELS
> dye
> smoke
WIND TUNNELS AIM
aim to improve the flow of air around ad object by streamlining its path
LIFT AND DRAG
oncoming air can potentially increase lift or decrease drag
ALLOWS ENGINEERS
able to have tight control on environmental variables
ENVIRONMENTAL VARIABLES
> wind speed
> direction
ADVANTAGES OF WIND TUNNELS
able to control winds and measure air resistance
DISADVANTAGES OF WIND TUNNELS
> specialised facilities
engineering bases
expensive
requires complex analysis
ANGULAR MOTION
movement of a body or a part of the body in a circular path about an axis of rotation
ECCENTRIC FORCE
a force applied outside the centre of mass resulting in angular motion
TORQUE
a measure of the turning (rotational or eccentric) force applied to the body
PRINCIPAL AXIS OF ROTATION
an imaginary line that passes through the centre of mass about which a body rotates (longitudinal / transverse / frontal)
LINEAR MOTION
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
LINEAR MOTION IS CREATED BY
direct force
> an external force passes through the centre of mass
ANGULAR MOTION IS CREATED BY
eccentric force
> an external force that passes outside the centre of mass
HOW TO ROTATE QUICKER
bring the body closer together
HOW TO ROTATE SLOWER
spread the body apart
TORQUE
a measure of the turning force applied to a body
A TORQUE IS WHAT TYPE OF FORCE
angular force
RADIAN
a unit of measurement of the angle through which a body rotates
RADIAN MEASUREMENTS
360 degrees = 2 pi radian
53.7 degrees = 1 pi radian
RADIAN MEASUREMENTS EQUIVALENT
radian is the equivalent of meters in angular motion
ANGULAR VELOCITY MEASUREMENT
radian per seconds
ECCENTRIC FORCE APPLIED
when an eccentric force is applied (a force applied away from the centre of mass) creates angular motion
DIRECT FORCE APPLIED
when a direct force is applied (a force applied towards the centre of mass) creates linear motion
THREE TYPES OF PLANES
> sagittal
frontal
transverse / horizontal
THREE TYPES OF AXIS
> longitudinal
frontal
transverse
TwirL
> Transverse plane
> Longitudinal axis
SomersaulT
> Sagittal plane
> Transverse axis
FlufF cartwheel
> Frontal plane
> Frontal axis
DISTANCE TIME GRAPHS
on the sheet of revision paper
ANGULAR MOTION EQUATION
angular momentum = moment of inertia x angular velocity
ANGULAR MOMENTUM MEASUREMENT
kgm² rad per second
MOMENT OF INERTIA MEASUREMENT
kgm²
ANGULAR VELOCITY MEASUREMENT
rad per second
ANGULAR MOMENT LINK
link to Newtons first law of motion
NEWTONS FIRST LAW LINK TO ANGULAR MOTION
> conservation of angular moment of an object or person
> an object remains at a constant state of angular momentum until acted upon by an external torque
MOMENT OF INERTIA
mass x distance from axis
ANGULAR VELOCITY IS
how fast something is moving
MOMENT OF INERTIA AND ANGULAR VELOCITY RELATIONSHIP
they need to be opposite
ANGULAR MOMENTUM EQUATION
mass x speed
MOMENT OF INERTIA DEFINITION
reluctance to change state of angular motion
ANGULAR VELOCITY
speed of how fast something is moving
TO INCREASE MOMENT OF INERTIA
> increase distance from axis
increase mass
increase both at the same time
RELATIONSHIP OF SPEED AND MOMENT OF INERTIA
the faster you move then the slower your moment of inertia is
RELATIONSHIP OF CENTRE OF MASS AND MOMENT OF INERTIA
the closer you are to the centre of mass then the lower your moment of inertia
ANGULAR VELOCITY EQUATION
angular displacement ÷ time taken
ANGULAR MOMENTUM DEFINITION
the quantity of angular motion possessed by a body
CONSERVATION OF ANGULAR MOMENTUM
angular momentum is a conserved quantity which remains constant unless acted upon by an external eccentric force or torque is applied
LINEAR MOTION
movement of a straight or curved line where all parts move the same distance, in the same direction over the same time
DIRECT FORCE
a force applied through the centre of mass resulting in linear motion
LINEAR MOTION DESCRIPTORS
> distance > displacement > speed > velocity > acceleration > deceleration
DISTANCE
the total length covered from start to finish positions
DISPLACEMENT
the shortest straight-line route from start to finish position
SPEED EQUATION
distance ÷ time taken
SPEED MEASUREMENT
measured in metres per second
VELOCITY MEASUREMENT
measured in metres per second
VELOCITY
the rate of change in displacement
VELOCITY EQUATION
displacement ÷ time taken
ACCELERATION MEASUREMENT
measured in metres per second per second
ACCELERATION
the rate of change in velocity
ACCELERATION EQUATION
(final velocity - initial velocity) ÷ time taken
DECELERATION
the rate of change in velocity (decrease or negative)
DISTANCE TIME GRAPH
a visual representation of the distance travel plotted against the time taken
GRADIENT
the slope of a graph at a particular moment in time
GRADIENT EQUATION
gradient = change in y axis ÷ change in x axis
SPEED TIME GRAPH
a visual representation of the speed of motion plotted against the time taken
VELOCITY TIME GRAPH
a visual representation of the velocity of motion plotted against the time taken
