Module 7 - Environmental contexts Flashcards
what are the forces affecting movement in water?
Resistance/ Drag - negative force
lift
propulsion - positive force in the direction we want to move
sink - force - overcome this resistance force
What is friction?
When two surface overlap and cause pressure and inertia to slow down
What is Archimedes principle?
the more fluid you can displace, the more buoyancy you can create: float more.
a force is applied to the object floating because the water is displaced.
What is density?
the mass of the atoms in an object.
a swimmer’s density is related to the body’s mass and volume.
- body composition
- air in the lungs
What is buoyancy?
equal to the weight of the volume of water that a body displaces.
the force that pushes the object to the surface.
center of buoyancy is the center of underwater mass
What happens when the centre of mass is not in line with the axis of rotation?
then the body will rotate back until the two points are lined up.
What is Drag?
the force that is acting opposite to the direction of motion
can push, pull, and tug on an object or body
preventing drag: become streamline
how can we delibrately take advantage of drag?
buy cupping or hands, paddling to propel ourselves forward in the water.
Pressure drag
produced by the shape/size of the body in water
high pressure is developed in front of you
turbulence flow (moving water) creates low pressure which pulls on the object.
Propulsion
force projection
water is thicker than air, easier to get reaction forces from.
moving yourself forwards
How can you move forwards efficiently in water?
push water opposite of the intended direction of travel.
overcome resistance forces through the use of streamline body positions to minimize drag and sinking.
What is CSA?
Contact Surface Area
can used to manipulate the frictional force by changing the weight per unit area.
how much of your foot is in contact with the surface, and how much you weigh.
how does CSA connect to N3L?
the force pressing an object into a surface is equal to the weight of that object pressing down into the surface.
create a frictional force
what are two types of frictional forces?
static - greater downwards pressure in the action - greater upwards force reaction from the surface.
dynamic (sliding, rolling) frictional forces
- less downward pressure, less upward force reaction from the surface.
- when your pushing force is greater than the friction force, the object moves.
How do we manipulate frictional force? (FF)
using special footwear, adapting to the contact surface area
allows the mover to adjust weight per unit area (WPUA)
the direction of motion of the surface area (shoe) is opposite of the direction of friction.
What is an Asymmetrical movement?
one side of the body is engaging in the complete opposite action as the other side of the body
- stance on one side, swinging on the other side
coordination
What happens to the BOS if there is less CSA?
decreased size of BOS, less stability, more mobility and acceleration.
stability and mobility work as opposites.
what are the 3 categories of movement?
functional movements - games, scoring, play, - outcome focused.
artistic movements - gymnastics, figure skating - achieving a function or outcome.
expressive movement - dance, the process instead of the outcome.
