Biomechanics Flashcards
what is the definition of moment of inertia?
a body’s resistance to a change in its state of angular/rotational force
what does a decrease moment of inertia result in?
increased rotational force
how do you increase moment of inertia?
having the body out
what is conservation of angular momentum ?
a spinning body will continue to spin indefinitely unless an external force acts on it
what is angular momentum ?
the rotational or angular motion possessed by an object
what is the fulcrum?
point around which the lever rotates
what is the force arm?
the distance between the fulcrum and the pointa t which the force is applied
what is the resistance arm ?
the distance between the fulcrum and the centre of the resistance
what is the input force?
force exerted on the lever
what is the output force?
force exerted by the lever
what is the most common lever in the body
3rd class
what factors effect the lever?
-length of the lever
-the inertia of the lever
-the amount of force
what is inertia?
an objects resistance to change its current state of position
what is newtons 1 law of motion?
objects will remain at rest unless acted on by an external force
what is newtons 3 law of motion?
for every action there will be an equal and opposite reaction eg coming of a swimming block
what is newtons 2 law of motion?
an objects acceleration is directly proportional to the force acting upon it indirectly proportional to its mass
what is the formula for newtons 2 law?
force=mass x acceleration
what happens when there is a greater momentum?
more force required to stop or slow the object
what is force - motion ?
the magnitude of the force and the direction of the force applied, more force=greater acceleration
what is force-time equation?
impulse=force x time
what is impulse?
the change in momentum
this is done by removing peak force
how is a larger impulse created?
increasing the range of motion in the prep phase
what is the coefficient of restitution ?
refers to the elasticity of an objects and measures the momentum that is conserved
how is COR measure?
-between 0-1
-0 being the least elastic
-1 being the most elastic
how is COR affected?
-the materials of the interacting surfaces
-velocity of collision
-temperature of the material
what is the definition of torque ?
a force that is produced via rotational movement around an axis from an eccentric force
how is torque increased?
-increase the force
-increase the distance away from the axis
-increase the radius
what is segmental interaction ?
the transfer of energy between body parts it is the way the body segments and interacts to meet the demands of a task
what are the 6 points to segmental interaction ?
-body parts move in a sequence to generate the largest force or acceleration possible
-movement starts with the largest strongest, slowest segments working through to the smallest and fastest resulting in summation of momentum
-the next segment begins to move as the preceding segment has reached maximum velocity
-the body needs to be well balanced to aid in the transfer of momentum across body segments
-follow through is important to prevent deceleration of the last segment and safe dissipation of force
-all forces are directed to the target
what is the coordination continuum ?
the sequencing approach to develop motion
what is the definition of balance?
the ability of something to maintain its position
how is balance improved?
-larger base support
-increasing surface area on the ground
-lowers centre of gravity
-maintains line of gravity in the middle of the base support
what is range of motion and what occurs when it is increased?
-the degree at which the body segment moves around a joint while in motion
-increase velocity
what are the three factors to optimal projection ?
- height of release
- projection angle
- velocity of release
what is turbulent flow?
flow in which the velocity at any point varies erratically.
less pressure
later seperation point
what is laminar flow?
a type of fluid flow in which fluid moves smoothly in individual streams
more pressure
early seperation point
what is the definition of Form Drag?
the resistance created by the pressure differential between the front and the back of an object moving through a fluid
-delaying seperation=decreased cross section
what is the definition of boundary seperation layers?
the point at which the boundary layer of fluid passing over the body/ object separates the surface
what is surface drag ?
the friction between the fluid and the surface of a moving object
what is wave drag?
the resistance formed by the creation of waves at the point where water and air interact
this drag comes from the creation of waves as an object moves through water
how to improve wave drag ?
-improve buoyancy
-making object more streamline
-improve technique
-boat craft will decrease wave drag
what is Bernoulli’s principle ?
-the velocity of the fluid flow determines the pressure system
-pressure on one side of an object is inversly proportional to the velocity on the samme side of the object as the velocity of the fluid increases the pressure decreases
how is torque effected?
force applied
length of moment arm
angle
what is the magnus effect?
- the pressure differential high on one side and low on the other creates lift force that causes the ball to move in the direction of the pressure differential
- magnus force changes the flight of the ball due to spin while moving through air
