Bio Mechanical Movements Flashcards
Projectile motion
refers to movement of an object or body as it travels through the air
horizontal displacement
shortest distance from the starting point to finishing point in a line to the ground
angle, speed and height of release determine horizontal displacement
angle of release
when landing height and release height are equal the optimum angle of release is 45 degrees
eg long jumper
when landing height is above release height the optimum angle of release is greater than 45 degrees
eg basketball shot
when landing height is below release height the optimum angle of release is lower than 45 degrees
speed of release
the greater the velocity of a projectile, the greater the horizontal displacement
eg in shot put the speed across the circle ensures the shot leaves the hand at maximum velocity
height of release
a greater height of release results in a greater horizontal displacement
gravity is constantly acting upon the mass of the shot put so they should try and release it as high as possible
factors affecting flight paths
weight and gravity affect projectiles whilst they are in the air and determine whether they will have a true or distorted parabola
true parabola
projectiles with a large mass have a large weight (gravity) force and small air resistance will follow a true parabola
- longer weight arrow (pointing down)
- the longer the flight path, the more time allowed for air resistance to have an affect
distorted parabola
in projectiles with a lighter mass, air resistance will have a larger effect meaning the flight path will deviate to a distorted parabola
-the shuttlecock starts off with high velocity from force of the racquet and slows down due to the effects of air resistance
fluid mechanics
concerened with the movement in liquids and gases and how forces affect the objects in it
drag force
dynamic fluid force
acts in the opposition to motion, has a negative effect on velocity
surface drag- relates to friction between the surface of an object and the fluid environment (skin drag)
form drag- impact of fluid environment on an object
relates to streamlining- shaping a body so it can move effectively through a fluid
slipstreaming- the wind hits the front cyclist and the cyclist behind uses the air pocket behind them, so they have to exert less energy
factors affecting drag
velocity- the greater the velocity of a body through a fluid, the greater the drag so streamlining is important to reduce drag
cross sectional area of moving body- can increase or reduce drag
large CSA increases drag so cyclists crouch low over the handlebars to reduce their CSA
shape+ surface characteristics- more streamlined, aerodynamic body reduces drag
lift force
causes a body to move perpendicular to the direction of travel
achieved when different air pressures act on an object
bernoulli’s principle
where air molecules exert less pressure the faster they travel and more pressure when they travel slower
BP in projectile
angle of attack is important as it changes the flow of air around the discus, air that travels over the top of the discus has to travel a longer distance than air underneath
air above travels at higher velocity so it has a lower pressure which creates an upward lift force and allows the discus to stay in the air for longer
BP in downward
downward lift force is required by cyclists, F1 driver etc
in cycling, low streamlined body over the handlebars means that air travelling over the top of the cyclist has to travel a shorter distance than underneath
the air above travels at slower velocity, creating a higher pressure so the bike can maintain a firm grip on the track
newtons 1st law
law of inertia (tendency to resist changes in states of motion)
an object will remain at rest or uniform motion unless acted upon by an external force, that will overcome its inertia
eg ball will remain at rest until it is kicked
eg person will remain still until they contract their leg muscles and force from muscle contraction which can overcome inertia
newtons 2nd law
force= mass x acceleration
if large enough force is applied an object will
-accelerate in the direction of force
-accelerate in proportion to the amount of force applied
eg the harder a ball is kicked, the faster the ball will go/accelerate in the direction the force has been applied
newtons 3rd law
law of action and reaction
for every action there is an equal and opposite reaction
eg when a player jumps (action) a force is exerted on the ground in order to gain height, the ground exerts an equal and opposite upward force on the player
scalars
measurements are described in size or magnitude
mass, distance, speed
vectors
measurements are described in magnitude and direction
weight, acceleration, displacement, velocity, momentum