Biomechanical movement Flashcards
what is fluid mechanics?
the study of an object or human body that travels through any liquid or gas
what is dynamic fluid force?
-study of fluids and how forces affect them
-movement of liquids and gases
- e.g: drag + lift
drag= cycling, sprinting, swimming
lift= ball, discus, javelin
what is drag force?
-anything that slows something down
-resistance force caused by the motion of the body travelling through a liquid
-acts against motion + negatively impacts velocity
-produced from air resistance + friction
what are the two types of drag force?
surface + form
what is surface drag force?
between object surface and fluid environment
what is form drag force?
between environment and object
What are the ways to reduce forces acting on a cyclist whilst racing?
- friction- by using thin/high pressured tyres + by streamlining
-reduce frontal cross-sectional area, creating a smooth flow around the cyclist
-reduce surface friction of air on a cyclist by changing body shape to smooth airflow behind cyclist
what are the factors that affect drag?
- velocity of the moving body- greater velocity= greater drag= reduced by streamlining
-cross-sectional area of moving body- larger area=greater drag
-shape + surface characteristics of a moving body- streamlined aerodynamic shape reduces drag
what is the Bernoulli principle for a discus?
-air molecules exert less pressure the faster they travel
-body forms an aerofoil shape - creating the angle of attack to the direction of motion
-air travels further and faster over the top of the discus = lower pressure on top
-Bernoulli force formed from high to low pressure
-air tries to move from high to low= lift force
-so flight path is assymetrical + flight path lengthens - so discus travels further
what is the Bernoulli principle for a cyclist?
-air molecules exert less pressure the faster they travel
-body forms an aerofoil shape - creating an angle of attack to the direction of motion
-air travels further and faster under cyclist = lower pressure under cyclist
-Bernoulli force applied from high to low pressure = down force
what is Newtons first law?
-Law of INERTIA
-everybody continues in its state of res tor motion in a straight line unless compelled to change that state by external forces exerted upon it
what is inertia?
the resistance of an object has to change its state of motion
what is Newtons second law?
-Law of Acceleration
-the rate of a body is proportional to the force causing it + the change that takes place in the direction in which the force act
-the rate of change of momentum of an object is directly proportional to the force causing the change
force= mass x acceleration
what is Newtons third law?
-Law of Action/Reaction
-to every action, there is an equal + opposite reaction
what does a vector quantity consist of?
magnitude and direction
what does a scalar quantity consist of?
only magnitude
what is the formula for speed?
distance/time
what is the formula for velocity?
displacement/ time
what is the centre of mass?
an imaginary point where we believe the mass of an object is concentrated
where is each component located in a first class lever?
from left to right: effort, fulcrum, load
what is the first class lever involved in?
neck and elbow extension
where is each component located in the second class lever?
from left to right: fulcrum, resistance, effort
what is the second class lever involved in?
plantarflexion of the ankle
where is each component located in the third class lever?
from left to right: fulcrum, effort, resistance
what is the third class lever involved in?
hip, knee, elbow flexion and knee extension
what is mechanical advantage?
when the force arm is longer than the resistance arm
> so you can move a larger load over a short distance, requiring little force
>small range of movement
>difficult to generate speed + distance
what is mechanical advantage dependent on?
the length of the effort arm and resistance arm
define effort arm.
distance between the fulcrum and effort
define resistance arm.
distance between the fulcrum and resistance
what is mechanical disadvantage?
when the resistance arm is longer than the force/effort arm
>cannot move heavy loads
>can move faster
>large ROM
what are the mechanical advantages of the second class lever?
– generate large forces
–has to lift whole body weight
what are the mechanical disadvantages of the second class lever?
–slow
–limited ROM
what are the mechanical advantages of the first + third class levers?
–larger ROM
–any resistance can be moved quickly
what are the mechanical disadvantages of the first + third class levers?
–cannot apply much force to move an object
what is the formula to work out mechanical advantage?
length of effort arm/ length of resistance arm
define mass.
the quantity of matter a body possesses
what is an impulse?
a measure of a force applied over time
what is the formula to work out impulse?
force X time
–newton seconds (Ns)
what is the formula for momentum?
mass X velocity
what does this impulse graph show ?
positive impulse is larger that the negative impulse = acceleration
what does this impulse graph show?
positive impulse is equal to the negative impulse = constant speed
what does this impulse graph show?
positive impulse is smaller than the negative impulse = deceleration
what are the external forces that can act on a person or object?
–air resistance
–gravity/weight
what is angular momentum?
the quantity of rotation a body possesses
what is the formula for angular momentum?
moment of inertia X angular velocity
what is angular velocity?
speed of rotation
what is the formula for angular velocity?
angular displacement/ time
what are the factors affecting the distance an object travels/ horizontal displacement
–height of release
–speed of release
–angle of release
what is the angle of release dependent on?
–release height
–landing height
what affects the flight path of an object?
– weight of the object
–air resistance acting on the object
what is a parabolic flight path?
the flight path of a projectile in the absence of air resistance
when does a parabolic flight path occur?
if the weight is the dominant force and the air resistance is less effective
what is horizontal displacement?
the shortest distance from the starting point to the finishing point
what is torque?
the force created that turns the body around an axis
how does a performer decrease their angular motion?
–increase their moment of inertia an decrease their angular velocity
–by opening their limbs
how does a performer increase their angular motion?
–decrease their moment of inertia and increase their angular velocity
–by tucking in their limbs
what is the first angular law?
a rotating body will continue with constant torque until a large enough external force is acted upon it
what is the second angular law?
the rate of change of angular motion is proportional to the force changing it
what is the third angular law?
when torque is applied, there will always be an equal and opposite force
