biomechanical movement Flashcards
angular motion definition
involves rotation
movement around a fixed point or axis
occurs when force is applied outside the centre of mass
transvers axis and sporting example
runs from side to side across body
e.g somersault rotates in a transverse axis
sagittal axis and sporting example
runs from front to back
e.g cartwheel rotates in sagittal axis
longitudinal axis and sporting example
runs from top to bottom
e.g multiple spin in ice skating rotates in longitudinal axis
what is a torque
turning force
the rotational consequence of a force
ways to increase torque
increasing size of force
-applying same force further away from axis of rotation
newtons first law of angular motion
a rotating body will continue to turn about its axis of rotation with constant angular momentum unless rotating force (torque) is exerted upon it
newtons first law of angular motion sporting example
e.g. ice skater will spin in air and continue to spin until they land on the ice when external force (torque) is exerted from the ice on their skates which changes the angular momentum
newtons second law of angular motion
rate of change of angular momentum of a body is proportional to the force (torque) causing it and the change that takes place in the direction in which the force (torque) acts
newtons third law of angular motion
when a force (torque) is applied by one body to another, the second body will exert an equal and opposite force (torque) on the body
sporting example of newtons third law of angular motion
e.g. goalkeeper tips the ball over the bar, they throw their arms up which causes the lower parts of their legs to go back
scalar quantity
measurements are only decribed in terms of size or magnitude
example of scalar quantity measurements
mass, distance, speed
vector quantity
when measurements are described in terms of size AND direction
example of vector quantity measurements
weight, acceleration, displacement, velocity
what is mass
quantity of matter the body possesses
how is weight calculated
mass(kg) x gravity(9.8)=weight (newtons)
distance definition
length of the path a body follows when moving from one position to another
displacement definition
shortest route in straight line between the starting and finishing points
is distance a scalar or vector quantity
scalar as only measures size
is displacement a scalar or vector quantity
vector as measures size and direction
speed definition
rate of change of distance
scalar quantity as does not consider direction
how do you calculate speed
speed= distance covered (m)divided by time taken (s)
velocity definition
refers to how fast a body travels in a certain direction
rate of change of displacement
velocity calculation
displacement divided by time taken
acceleration definition
rate of change of velocity
when velocity increases, positive acceleration takes place
when velocity decreases, negative acceleration takes place
acceleration calculation
change in velocity divided by time
momentum definition
product of mass and velocity of an object
projectile motion definition
movement of an object or person travelling through the air
in sport, as soon as ball released, becomes a projectile
factors affecting the horizontal displacement of a projectile motion
speed of release
angle of release
height of release
study tip: HAS
angle of release
optimum angle of release dependent on landing height and release height
what is the optimum angle of release when both landing height and release height are equal
optimum angle of release=45 degrees
e.g long jumper
what is optimum angle of release when release height is below landing height
optimum angle of release needs to be greater then 45 degrees
e.g basketball shot
what is optimum angle of release when landing height is below release height
optimum angle of release needs to be below 45 degrees
e.g shot put
speed of release
greater the release velocity of projectile, greater horizontal displacement travelled
e.g shot put the speed of the rotation across the circle ensures shot leaves hand at max velocity. therefore, greater horizontal displacement achieved
height of release
greater the release height, greater the horizontal displacement travelled
what two forces affect projectiles whilst in air
weight
air resistance
what is important about weight and air resistance
decide whether a projectile has a flight path that is true parabola or a distorted parabola
what is a parabola
curve that is symmetrical at its highest point
what projectiles have a true parabola flight path
large weight force, small air resistance force
sporting example of true parabola flight path
shot put as large weight small air resistance
distorted parabola
low weight force, high air resistance
sport example of distorted parabola flight path
shuttlecock in badminton
has lighter mass and unusual shape that increases its air resistance
vertical component
upward motion of an object
arrow will be upwards
horizontal component
horizontal motion of an object
arrow will be left or right
fluid mechanisms
study of object or body that travels through any liquid or gas
e.g swimmers travel through water
tennis ball travels through air
both can be slowed down by friction or drag
drag force
slows something down
resistance force caused by motion of body travelling through liquid
acts in opposition to direction of motion
negative effect on velocity
produced from air resistance and friction
cyclist will try to minimise drag so they can increase their velocity
what are the two types of drags
surface drag
form drag
surface drag
relates to friction between surface of an object and the fluid environment
swimmers wear specialised smooth clothing, shave off body hair to reduce surface drag
wearing streamline clothing
form drag
relates to impact of environment on an object
e.g swimmer has to create thinnest and straightest form in water to reduce form drag
factors that reduce and increase drag
velocity of moving body
cross sectional area of moving body
shape and surface characteristics of moving body
velocity of the moving body
greater the velocity, greater the drag force
cyclist will experience greater air resistance, increase drag
reduce effects of drag include streamlining the body
cross sectional area of the body
large cross sectional area of body increases drag
cyclists reduce drag by crouching forwards over handlebars instead of sitting upright as reduces cross sectional area
shape and surface characteristics of a moving body
more streamlined, aerodynamic shape reduces drag
drag resistant clothing
aerodynamic helmets with air ducts to reduce drag
shaving off all body hair for swimmers to reduce drag
either bold or wear swimming cap
Bernoulli principle
downward lift force
lift force
discus in bernouili principle
air that travels over the top of discus has to travel at a longer distance then air underneath
air above discus travels at faster velocity, lower pressure
air that travels below has shorter distance to travel so travels at higher pressure
higher pressure below discus causes lift force and allows discus to stay in air for longer, increasing horizontal displacement
cycling in Bernoulli principle
air travelling over the top travels a shorter distance then air underneath
air above travels at slower velocity, higher pressure
creates a downward lift force
