biomechanics

a body continues in a state of rest or at a constant velocity unless acted upon by an external force

the rate of momentum experienced by the object is proportional to the size of the force and takes lace in the direction which the force acts

every action has an equal and opposite reaction

linear motion, angular motion, general motion

movement of a body in a straight or curved line where all parts are moving the same distance in the same direction over the same time

100m sprint/swim

newtons 1st law

movement of a body or body part in a circular path about an axis of reaction

newtons 1st law

shoulder during cricket bowl

direct force applied to the body through the COM

eccentric force applied to a body outside of the COM

it is a combination of linear and angular motion

swimming, running, cycling

the trunk moves in linear motion and as a result of other body parts moving in angular motion and shoulder and hip joint

the rate of change in displacement

m/s

velocity=displacement/time

the quanity of motion possessed by a moving body

kgm/s

momentum= mass X velocity

the rate of change of velocity

m/s/s

(finial velocity-initial velocity)/time taken

1. increase force/velocity/speed

2. increase friction

3. reduce mass/weight

4. improve technique

5. decrease air resistance

the point where all the mass of the body tends to be concentrated and balanced in all directions

1. body position

2. athlete body shape

3. gender

a stable body position will enable an athlete to resist motion

an imaginary line which extends from the centre of mass directly to the ground

1. increase mass of body

2. increase size of base support

3. lower COM

4. increase number of contact points

5. bring line of gravity inside the base support

a push or pull that alters the state of motion of a body

newtons

force= mass x acceleration

the overall force acting on a body when all individual forces have been considered

weight and reaction force

friction and air resistance

gravitational force that the Earth exacts on a body

whenever there is a point of contact between two bodies there will alway be this force

the force that opposes motion of a body travelling through air

the force that opposes the motion of two surfaces in contact

sliding friction, direction friction, parallel friction

occurs when two surfaces have a tendency to slide over one another

acts in the opposite direction to motion

acts parallel to the two surfaces in contact with eachother

1. roughness of footwear/object

2. roughness of ground

3. size of down force

4. temperature of surface

1. shape of object

2. velocity

3. frontal cross sectional area

4. smoothness of surface

1. technique

2. footwork

3. conditions

4. body shape

1. force

2. air resitsance

3. body shape

the perpendicular distance from the fulcrum to the load

the perpendicular distance from the fulcrum to the effort

fulcrum in the middle

load in the middle

effort in the middle

header (fulcrum= joint between atlas and skull, load= weight of head, effort= trapezius )

pirouette in ballet (fulcrum= joint between phalanges and metatarsals, load= weight of body, effort= plantarflexion)

bicep curl (fulcrum= elbow, load= weight, effort= biceps brachii)

2nd class

ability to move large load with small effort, larger effort arm than load arm

3rd class lever

lever struggles with heavy load, load arm is longer than the effort arm

the study of motion, limbs and movement through video, 3D analysis.

improve technique, improve posture, helps with injury rehabilitation

accessibility, cost, requires specialist data to interpret

rectangular metal plates in the ground that measure force

to design prothesistics, to improve technique, rehabilitation

expensive, requires specialist training, must be calibrated

they are used to stimulate air resistance

improve technique (aerodynamic), to test equipment design

accessibility, cost, training to interpret data

distance, displacement, speed, velocity, acceleration

total length from start to finish (m)

the shortest straight line route from start to finish (m)

the rate of change in distance (m/s)

the rate of change in displacement (m/s)

the rate of change in velocity (m/s/s)

distance/time graphs, speed/time graphs, velocity/time graph

a turning force- the greater the eccentric force, the greater the angular motion

1. longitudinal (from head to toe)

2. transverse (from side to side)

3. frontal (from front to back)

radians (rad/s)

the rate of change in angular displacement

AV (rad/s)= angular displacement (rad)/time (s)

the resistance if a body to change its state of angular motion

MI (kgm2)= mass(kg) x distribution of mass from axis of rotation (m2)

mass

distribution of mass from the axis of rotation

the greater the mass, the greater the moment of inertia, decreases angular velocity

close mass distribution from axis, decrease moment of inertia, increase angular velocity

the quantity of angular motion possessed by a body

AM= MI x AV

AM is constant. As MI increases, AV decreases

1. velocity (greater velocity= greater drag and AR)

2. frontal cross-sectional area (larger= greater drag and AR)

3. shape (more streamlined= less drag and AR)

4. surface characteristics (smooth surface= less drag and AR)

movement of a body through air flowing a curved flight path under the force of gravity

1. speed of release

2. angle of release

3. height of release

4. aerodynamics

the greater force applied to projectile, greater acceleration, so travels further

45- optimal angles= greatest distance

less than 45- not enough height

a uniform curve, symmetrical about its highest point, unaffected by air resistance caused by a dominant weight force

asymmetric about its highest point caused by the dominant force of air resistance on the projectile

the higher the velocity of air flows the lower the surrounding pressure

aerofoil shape causes air to travel a greater distance with a greater velocity so low pressure above, air travels a shorter distance so lower velocity so high pressure below, air moves from high to low pressure down the pressure gradient so creates a lift force