BIOMECHANICS

Question 1

Fluid mechanics

Answer 1

study of fluids and how forces affect them

Question 2

drag force

Answer 2

Resistance force caused by motion of moving body through fluid slowing it down.
Acts in opposite direction of motion.

Question 3

2 different types of drag

Answer 3

• surface drag

- form drag

Question 4

surface drag

Answer 4

friction between the surface of an object + fluid environment. swimmers were specialised clothing to reduce

Question 5

form drag

Answer 5

impact of fluid environment on the object. Forces affecting the leading edge of an object increase form drag and forces affecting the trailing edge reduce drag. Related to streamlining.

Question 6

streamlining

Answer 6

shaping a body so it can move effectively and quickly through a fluid

Question 7

factors increasing and reducing drag

Answer 7

• velocity of moving body
• crosssectional area of moving body
• shape and surface characteristics of moving body

Question 8

drag is produced from …

Answer 8

air resistance and friction

Question 9

example of surface drag

Answer 9

swimmers wear specialised clothing to reduce surface drag

Question 10

example of form drag

Answer 10

swimmer has to created straightest form as they move through the water and cyclist will use others riders slipstream. 2nd cyclist can save up to 30% more energy

Question 11

how velocity of moving body affects drag

Answer 11

the greater the velocity the greater the drag force. so streamlining is important.

Question 12

how cross sectional area of moving body affects drag

Answer 12

large cross-sectional area increases drag. In Tour de France reducing their cross sectional area is vital to reduce drag through crouching over the handlebars rather than sitting upright.

Question 13

how shape and surface of moving body affect drags

Answer 13

regularly making drag resistant clothing to achieve gains in speed. In cycling clothing with ridges and aerodynamic helmet have been designed to reduce the effects of drag. Badminton shuttlecock has a larger drag force from air resistance.

Question 14

Bernoulli’s principle definition

Answer 14

where air molecules exert less pressure the faster they travel and more pressure when slower.

Question 15

lift force definition

Answer 15

causes a body to move perpendicular to direction of travel eg. discuss allowing it to stay in air longer

Question 16

what causes lift

Answer 16

when different air pressures act on an object. Air that travel faster has a lower pressure.

Question 17

angle of attack definition

Answer 17

the tilt of a projectile relative to airflow

Question 18

why is angle of attack important

Answer 18

it changes the flow of air around the discuss so that air travels over the top of the discuss has to travel a longer distance than air underneath. This results in a faster velocity creating a lower pressure. The lower pressure above the discuss creates an upward lift force allowing the discuss to stay in the air for longer

Question 19

what happens if angle of attack is too large

Answer 19

lift is reduced and drag increases causing discuss to stall.

Question 20

what is the optimum angle of attack for a discuss

Answer 20

25-40 degrees

Question 21

formula 1 downward lift force example

Answer 21

formula 1 car, cyclists and speed skiers. In formula 1 the air travels over car at a shorter distance due to angle of spoiler. So air above car travels at slower velocity with more pressure creating a downward lift force so tyres maintain a firm grip on track.

Question 22

cyclist downward lift force

Answer 22

low streamlined body over handlebars means air travels over top of cyclist and travels a shorter distance than air underneath. Air travels at a slower velocity at a higher pressure creating a downwards lift force allowing tyres of bike to maintain firm grip on track.

Question 23

Drag force has a negative effect on…

Answer 23

Velocity

Question 24

newtons first law

Answer 24

law of inertia. a force is required to change state of motion

Question 25

newtons second law

Answer 25

law of acceleration. The magnitude and direction of force determines the magnitude and direction of acceleration.

Question 26

newtons third law

Answer 26

law of action and reaction. for every force there is an equal and opposite reaction force.

Question 27

factors affecting stability

Answer 27

• height of centre of mass
• area of base of support
• position of line of gravity
• mass of performer

Question 28

mechanical advantage 1st class and 3rd class

Answer 28

large range of movement and any resistance can be moved quickly

Question 29

mechanical disadvantage 1st class and 3rd class

Answer 29

cant apply much force to an object

Question 30

mechanical advantage 2nd class

Answer 30

generate larger forces has to lift whole body weight

Question 31

mechanical disadvantage 2nd class

Answer 31

slow with limited range of movement

Question 32

impulse

Answer 32

time it takes a force to be applied to an object or body

Question 33

factors affecting horizontal displacement

Answer 33

• height of release
• angle of release
• speed of release

Question 34

angle of release when landing height is above release height

Answer 34

more 45 degrees

Question 35

angle of release when landing height is below release height

Answer 35

less 45 degrees

Question 36

speed of release

Answer 36

greater speed of release the greater the horizontal displacement

Question 37

height of release

Answer 37

greater release height increases horizontal displacement as force of gravity is constantly acting on object

Question 38

what two forces affect projectiles

Answer 38

weight/gravity and air resistance

Question 39

parabola

Answer 39

uniform curve that is symettrical at highest point