Bio Mechanical Movements

Question 1

Projectile motion

Answer 1

refers to movement of an object or body as it travels through the air

Question 2

horizontal displacement

Answer 2

shortest distance from the starting point to finishing point in a line to the ground
angle, speed and height of release determine horizontal displacement

Question 3

angle of release

Answer 3

when landing height and release height are equal the optimum angle of release is 45 degrees
eg long jumper
when landing height is above release height the optimum angle of release is greater than 45 degrees
eg basketball shot
when landing height is below release height the optimum angle of release is lower than 45 degrees

Question 4

speed of release

Answer 4

the greater the velocity of a projectile, the greater the horizontal displacement
eg in shot put the speed across the circle ensures the shot leaves the hand at maximum velocity

Question 5

height of release

Answer 5

a greater height of release results in a greater horizontal displacement
gravity is constantly acting upon the mass of the shot put so they should try and release it as high as possible

Question 6

factors affecting flight paths

Answer 6

weight and gravity affect projectiles whilst they are in the air and determine whether they will have a true or distorted parabola

Question 7

true parabola

Answer 7

projectiles with a large mass have a large weight (gravity) force and small air resistance will follow a true parabola

• longer weight arrow (pointing down)
• the longer the flight path, the more time allowed for air resistance to have an affect

Question 8

distorted parabola

Answer 8

in projectiles with a lighter mass, air resistance will have a larger effect meaning the flight path will deviate to a distorted parabola
-the shuttlecock starts off with high velocity from force of the racquet and slows down due to the effects of air resistance

Question 9

fluid mechanics

Answer 9

concerened with the movement in liquids and gases and how forces affect the objects in it

Question 10

drag force

Answer 10

dynamic fluid force
acts in the opposition to motion, has a negative effect on velocity
surface drag- relates to friction between the surface of an object and the fluid environment (skin drag)
form drag- impact of fluid environment on an object
relates to streamlining- shaping a body so it can move effectively through a fluid
slipstreaming- the wind hits the front cyclist and the cyclist behind uses the air pocket behind them, so they have to exert less energy

Question 11

factors affecting drag

Answer 11

velocity- the greater the velocity of a body through a fluid, the greater the drag so streamlining is important to reduce drag
cross sectional area of moving body- can increase or reduce drag
large CSA increases drag so cyclists crouch low over the handlebars to reduce their CSA
shape+ surface characteristics- more streamlined, aerodynamic body reduces drag

Question 12

lift force

Answer 12

causes a body to move perpendicular to the direction of travel
achieved when different air pressures act on an object

Question 13

bernoulli’s principle

Answer 13

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

Question 14

BP in projectile

Answer 14

angle of attack is important as it changes the flow of air around the discus, air that travels over the top of the discus has to travel a longer distance than air underneath
air above travels at higher velocity so it has a lower pressure which creates an upward lift force and allows the discus to stay in the air for longer

Question 15

BP in downward

Answer 15

downward lift force is required by cyclists, F1 driver etc
in cycling, low streamlined body over the handlebars means that air travelling over the top of the cyclist has to travel a shorter distance than underneath
the air above travels at slower velocity, creating a higher pressure so the bike can maintain a firm grip on the track

Question 16

newtons 1st law

Answer 16

law of inertia (tendency to resist changes in states of motion)
an object will remain at rest or uniform motion unless acted upon by an external force, that will overcome its inertia
eg ball will remain at rest until it is kicked
eg person will remain still until they contract their leg muscles and force from muscle contraction which can overcome inertia

Question 17

newtons 2nd law

Answer 17

force= mass x acceleration
if large enough force is applied an object will
-accelerate in the direction of force
-accelerate in proportion to the amount of force applied
eg the harder a ball is kicked, the faster the ball will go/accelerate in the direction the force has been applied

Question 18

newtons 3rd law

Answer 18

law of action and reaction
for every action there is an equal and opposite reaction
eg when a player jumps (action) a force is exerted on the ground in order to gain height, the ground exerts an equal and opposite upward force on the player

Question 19

scalars

Answer 19

measurements are described in size or magnitude

mass, distance, speed

Question 20

vectors

Answer 20

measurements are described in magnitude and direction

weight, acceleration, displacement, velocity, momentum

Question 21

mass

Answer 21

amount of matter an object possesses

kg

Question 22

distance

Answer 22

the length between the start point and finish point

metres m

Question 23

speed

Answer 23

rate at which an object travels a specified distance
m/s
speed= distance/ time

Question 24

weight

Answer 24

gravitational force exerted on an object
newtons N
weight= mass x GFS

Question 25

velocity

Answer 25

rate of change of displacement in a certain direction ms displacement/time

Question 26

momentum

Answer 26

product of the mass and velocity of an object | kg m/s

Question 27

displacement

Answer 27

total length of the path an object travels between its start and end points (400m track has 0 d) m

Question 28

acceleration

Answer 28

rate of change of velocity m/s2 change in velocity/time

Question 29

angular motion

Answer 29

movement around a fixed point or axis eg somersault occurs when a force is applied outside the centre of mass 1st law- rotating body will continue in state of angular motion unless an external force (torque) acts upon it 2nd law- rate of change of angular momentum of a body is proportional to the force causing it and the change that takes place in the direction in which a force acts 3rd law- when a force is applied by one body to another, the second body will exert an equal and opposite force on the other body

Question 30

altering angular velocity

Answer 30

angular momentum=moment of inertia x angular velocity to slow down- gymnast will increase moment of inertia by extending their body or opening out to increase speed they will decrease moment of inertia by tucking body in or bringing arms in

Question 31

centre of mass

Answer 31

point of balance in the body, where weight is considered to act

Question 32

factors affecting stability

Answer 32

height of centre of mass- lowering centre of mass will increase stability position of line of gravity - should be central over the base of support to increase gravity area of base of support- larger is more stable as there is more contact points

Question 33

first class lever

Answer 33

``` fulcrum in middle, effort arrow pointing down flexion in head and neck extension at elbow MA- large ROM and moves quickly MD- can't apply much force ```

Question 34

second class lever

Answer 34

resistance in middle, effort arrow up plantarflexion at ankle mechanical adv of generate large force mech dis slow limited ROM

Question 35

third class lever

Answer 35

effort in middle, arrow up all other joints MA- large ROM and moves quickly MD- can't apply much force

Question 36

effort arm

Answer 36

shortest distance between fulcrum and application of effort

Question 37

resistance arm

Answer 37

shortest distance between fulcrum and resistance

Question 38

mechanical advantage

Answer 38

effort arm longer than resistance arm lever system can move large load over short distance requiring little effort small range of movement

Question 39

mechanical disadvantage

Answer 39

resistance arm longer than effort arm lever system cannot move heavy load but can move it faster large range of movement

Question 40

forces acting upon performer (linear)

Answer 40

internal force applied when skeletal muscles contract external force comes from outside a body eg gravity, friction

Question 41

weight and gravity

Answer 41

weight = vertical force gravitational force that the earth exerts on a body greater mass = greater weight force pulling it down weight= mass x acceleration

Question 42

friction

Answer 42

friction occurs when two or more bodies are in contact with eachother acts in opposition to motion static friction= before object starts to move sliding friction= when friction acts between surfaces that are moving relative to eachother

Question 43

friction affected by

Answer 43

temperature mass of body-larger mass means more friction surface characteristics

Question 44

air resistance

Answer 44

opposes motion of a body travelling through air

Question 45

AR affected by

Answer 45

velocity- faster velocity, greater air resistance cross sectional area- larger will be more air resistance shape and surface characteristics- streamlined will have less air resistance

Question 46

force diagrams

Answer 46

friction arrow points forwards weight arrow points downwards AR arrow points backwards

Question 47

vector diagram

Answer 47

eg high jump large arrow pointing up and diagonal due to large vertical displacement eg long jump large arrow pointing forward due to large horizontal component, trying to go as far as possible

Question 48

impulse

Answer 48

force x time time it takes a force to be applied to body increase in impulse will result in increase in rate of change of momentum = increase in velocity impulse can be used to increase momentum by -increasing muscular force applied -increasing time in which force is applied

Question 49

impulse to decrease momentum

Answer 49

increasing the time in which forces act upon body | eg flexing hips, knees and ankles when landing extends the time of the force on the ground

Question 50

force time graphs (impulse)

Answer 50

impulse is represented by an area under a force time graph in 100m sprint the graph is only concerned with horizontal forces -at start= small neg impulse and large positive impulse net impulse is positive so sprinter is accelerating -middle= foot makes contact with ground (neg impulse) athlete pushes off track (pos impulse) pos = neg impulse so moving at constant velocity -end= higher negative impulse as they are slowing down decelerating