Fluid Mechanics

Question 1

define projectile motion

Answer 1

a form of motion in which an object is thrown

Question 2

list the 3 factors affecting horizontal displacement of projectiles

Answer 2

Angle of release
Speed of release
Height of release

Question 3

what are the factors that minimise drag

Answer 3

body position
Surface characteristics
Clothing
Shape of equipment

Question 4

what is a parabola

Answer 4

a symmetrical curve

Question 5

define aerodynamic

Answer 5

the movement of air past an object

Question 6

define drag

Answer 6

a force acting opposite to the relative motion of any object moving with respect to a surrounding fluid

Question 7

define lift force

Answer 7

force that is perpendicular to the oncoming force that results in lift

Question 8

what is the Bernoulli effect

Answer 8

an increase in the speed of a fluid occurs simultaneously with a decrease n pressure or decrease in the fluid’s potential energy

Question 9

define the Bernoulli effect

Answer 9

Relationship between velocity and pressure acting on an object as it
moves through a fluid/air, for example a ball in flight.

Question 10

what technological advancements can be used to identify potential drag in cycling

Answer 10

computer analysis

Question 11

what happens when the velocity of fluid increases

Answer 11

the pressure exerted by that fluid decreases

Question 12

does a cyclist have high or low fluid friction and what could be doe to alter this

Answer 12

high
- reduce front cross sectional area by crouching low
- helmet designed to minimise turbulent flow

Question 13

what angle of release is required for an object to achieve optimum distance moved before landing

Answer 13

45 degrees

Question 14

define hydrodynamic

Answer 14

the movement of water past an object

Question 15

what type of flow does fluid friction rely upon

Answer 15

laminar flow

Question 16

define Magnus effect

Answer 16

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.

Question 17

what is Laminar flow

Answer 17

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

Question 18

what are the 5 characteristics fluid mechanics is affected by

Answer 18

velocity
drag force
mass
streamlining
surface characteristics

Question 19

as velocity increases what increases

Answer 19

air resistance

Question 20

what is the result of turbulent flow

Answer 20

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

Question 21

what creates turbulent flow

Answer 21

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

Question 22

what 4 forces affect the drag force of a swimmer

Answer 22

Forward cross sectional area
Surface area in contact with the water
Surface effects
Speed

Question 23

why does water create more drag

Answer 23

water is denser than air

Question 24

how do dimples (in clothing, equipment etc.) help to decrease drag force

Answer 24

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