Fluid Mechanics Flashcards
A Level Pe Paper 1 (25 cards)
define projectile motion
a form of motion in which an object is thrown
list the 3 factors affecting horizontal displacement of projectiles
Angle of release
Speed of release
Height of release
what are the factors that minimise drag
body position
Surface characteristics
Clothing
Shape of equipment
what is a parabola
a symmetrical curve
define aerodynamic
the movement of air past an object
define drag
a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid
define lift force
force that is perpendicular to the oncoming force that results in lift
what is the Bernoulli effect
an increase in the speed of a fluid occurs simultaneously with a decrease n pressure or decrease in the fluid’s potential energy
define the Bernoulli effect
Relationship between velocity and pressure acting on an object as it
moves through a fluid/air, for example a ball in flight.
what technological advancements can be used to identify potential drag in cycling
computer analysis
what happens when the velocity of fluid increases
the pressure exerted by that fluid decreases
does a cyclist have high or low fluid friction and what could be doe to alter this
high
- reduce front cross sectional area by crouching low
- helmet designed to minimise turbulent flow
what angle of release is required for an object to achieve optimum distance moved before landing
45 degrees
define hydrodynamic
the movement of water past an object
what type of flow does fluid friction rely upon
laminar flow
define Magnus effect
The generation of a sideways force on a spinning object due to the
pressure differences that develop as a result of velocity changes caused
by the spinning object, e.g. a ‘curve’ on a served tennis ball.
what is Laminar flow
when an object which is uniform in shape travels smoothly through the air the layers of air flow past in a smooth symmetrical flow lines because the layer of air directly in contact with the object (boundary layer) is slowed down by friction
what are the 5 characteristics fluid mechanics is affected by
velocity
drag force
mass
streamlining
surface characteristics
as velocity increases what increases
air resistance
what is the result of turbulent flow
Drag force because air is fast moving at the back of an object it has relatively low pressure in comparison to the front which causes a force pulling the object back as objects will always move from high to low pressure
what creates turbulent flow
when the boundary layer is unable to remain in contact with the surface of an object so breaks away forming fast moving eddies of air
what 4 forces affect the drag force of a swimmer
Forward cross sectional area
Surface area in contact with the water
Surface effects
Speed
why does water create more drag
water is denser than air
how do dimples (in clothing, equipment etc.) help to decrease drag force
they create mini bits of turbulence which gets sucked to the object keeping the boundary layer close all the way around it delaying the separation point = fewer/smaller vortexes/eddies behind the object
