Download Biomechanical principles of motion through air and water.

Biomechanical principles of
motion through air and water.
(chapter 5)
By Georgia and Cade
Key knowledge
• Projectile motion (including the human body
as a projectile), Magnus effect, spin (back spin,
top spin, side spin), height of release, angle of
release, velocity of release, angle of projection
and flight path (trajectory).
• In human movement, the two mediums that we
generally perform in are air and water.
• Air and water both effect the motion of an object as it
moves.
• Water and air, like all gases and liquids, are fluids, so both
exert forces on the body or an object as it moves
• Because of this, it is much harder to ride into a head wind
than it is to ride with a tail wind, swimming out from a
beach in a ocean is much harder than returning to shore.
• Therefore, cyclists, downhill skiers, swimmers and runners
try to streamline their bodies as much as possible.
Projectile motion
• Anything that is launched into the air and
affected by forces of gravity and air resistance
can be considered a projectile. In sport and
physical activity, the human body is often a
projectile.
• In athletics, diving and gymnastics, athletes
can be required to project themselves into the
air
Vertical and horizontal components
• Anything launched into the air that can be considered a projectile will
have horizontal and vertical components.
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Factors affecting the path of a projectile:
-angle of projection (or release)
-speed of release (or projection)
-height of release (or projection)
• The angle of projection is the angle at which an object is released into the
air.
• There are three shapes a flight path can form, depending on the angle od
release: vertical shape (straight up and down), parabolic (when projectile
is between 0-90 degrees), parabola (object projected at 0 degrees or
perfectly horizontal).
Human movement through air and
water
Laminar and turbulent flow.
• When an object moves through a fluid medium (air
or water) the air or water will flow in smooth,
parallel layers around the object, this is called
laminar flow.
Magnus effect
• Lift can be generated by spinning objects. A spinning object
increases the speed of fluid on one side and decreases it on
the other. This will create regions of high and low pressure on
either side of the object, generating lift.
• This pressure creates a Magnus force, which is a lift force that
will act from the area of high pressure to the area of low
pressure, causing the object to deviate in the direction of the
spin.
• This deviation is known as the
Magnus Effect