Unit 4 SEHS IB HL

kinematics

study of motion of bodies and objects without forces

kinetics

study of motion with forces

linear motion

motion in a straight line

curvilinear motion

motion in a curve

angular motion

motion around an axis

general motion

linear and angular motion together

linear motion sports example

ice puck across the floor

curvilinear motion sports example

javelin through the air

angular motion sports example

gymnast rotating on a high bar

general motion sports example

running in a stright line as our limbs rotate

Vector

measurement that has magnitude and direction

Scalar

measurement that only has magnitude

distance

path travelled from A to B

Displacement

change of position of a body

speed definition

time taken to cover a certain distance

speed formula

distance/time

Velocity definition

the time taken to change position

velocity formula

change in displacement / time

acceleration definition

a change in velocity in a given period of time

acceleration formula

change in velocity/change in time

force

the push or pull acting on an object

resultant motion

the sum of the forces acting on an object

Force formula

Force = Mass x Acceleration

weight formula

mass x gravity

Newton's first law (inertia)

an object will remain at rest or in constant motion unless acted upon by an external force

Newton's second law (acceleration)

F=MxA

Newton's third law

for every action there is an equal and opposite reaction

the centre of mass

a mathematical point around which the mass of an object is evenly distributed

base of support

the larger the base of support the greater the stability

principle of summing joint forces

when the forces from your muscles add up in the same direction, they make your movements more powerful

linear impulse formula

force x time

Moment of Inertia

the resistance to rotation

Angular Momentum formula

moment of inertia x angular velocity

collisions

when two or more objects collide

conservation of linear momentum during collisions

During a collision, the total linear momentum of the objects are conserved

coefficient of restitution

measures from 0-1 how much energy is retained after impact

1 coefficient of restitution

perfectly elastic no energy lost

0 coefficient of restitution

inelastic, no bounce

friction

a force that opposes motion between two surfaces in contact

coefficient of friction

The ratio of the force of friction

low coefficient of friction example

steel on ice

high coefficient of friction example

rubber sole on ground

static friction

friction that occurs on objects that are not moving

dynamic friction

friction that opposes the movement of an object

friction force and applied force on an object

when the force applied to a static object is enough to overcome static friction, the object begins to move

work formula

force x distance

power formula (Change)

change in work done/change in time

power formula (product of)

P= force x velocity

muscular power

application of strength and speed of a movement

projectile motion

an object dropped or thrown in the air that is acted upon by only the forces of gravity and air resistance

what is air resistance being negligible

air resistance has no effect, gravity is the only force and only vertical velocity changes

when would air resistance be negligible

when objects are small, dense and smooth or travelling at low speeds in thin air, or in short distances

three initial conditions of projection

initial velocity, angle of projection and height of release

when projection height is same as landing height

throw at 45 degree angle

when projection height is below landing height

throw above 45 degree angle

air resistance on fast-moving objects

high air resistance, faster deceleration

environmental conditions that impact forces acting on an object

temperature, humidity, wind, salinity of water and altitude

at high altitudes, objects...

travel faster and farther as there is less drag

buoyancy

the force acting vertically on objects partially immersed in fluid

archimedes' principle

the buoyant force is equal to the weight of the fluid displaced

for an object to float...

the buoyancy force must be greater than equal to the weight of the object

Drag force

a force that opposes the motion of an object through a fluid

surface drag

as a body moves through a fluid, outer surface of the body catches a layer of fluid nearby

how to minimize surface drag

wearing smooth things to reduce the interaction

surface drag is affected by

velocity, surface area and nature of the surface

form drag

when a body pushes against a fluid, a fluid pushes back

form drag is affected by

frontal area, shape and velocity

wave drag

when a body moves along the surface of a fluid, fluid is displaced to form a wave and swimmers loose kinetic energy

laminar boundary layers

boundary layer with molecules smoothly moving in same direction

turbulent boundary layer

boundary layer interacting with rough surfaces

Bernoulli's Principle

as the velocity of a fluid increases, the pressure exerted by the fluid decreases and a pressure difference is created

Bernoulli's principle in a ball

ball rotates towards the lower pressure, the pressure difference causes the ball to curve as lift is also created

Magnus force

lift force created by spin

define skill

consistent production of goal-oriented movements which are learned and specific to a task

four types of skills

motor, cognitive, perceptual and perceptual motor

motor skills

movements with barely any thinking

cognitive skills

requiring heavy thinking

perceptual skills

involving interpreting sensory information

perceptual-motor skills

combination of perception and movement

ability

traits a person is born with that enables one to perform skills

skill is..

ability + a selection of an appropriate technique

performance in skill learning

a temporary occurrence fluctuating

learning in skill learning

the process of acquiring consistency

transfer of learning (positive, negative or zero)

the effect that practice of one task has on the learning or performance of another

skill to skill transfer

throwing a ball to throwing a javelin

practice to performance transfer

batting against a machine to batting against an opponent in a game

abilities to skills transfer

improving dynamic strength to start races better

bilateral transfer of skills

learning to kick with a non-dominant side

stage to stage transfer of skills

from 3v3 to team v team

principles to skills transfer

learning that long levers aid throwing to throwing a javelin

information processing theory

the system that we take in information and use it to make a decision and produce a response

three phases of learning

cognitive, associative, autonomous

cognitive phase of learning

lots of thinking and mistakes, movements are inconsistent

associative phase of learning

practices movements, fewer errors and uses feedback

autonomous phase of learning

skill becomes automatic, consistent with low attention

traditional linear pedagogy

based on information processing theory and cognitive stages, teacher centred, movements should be broken down

nonlinear pedagogy

based on ecological dynamics approach, teachers modify constraints, learner centered approach

Exteroceptors

provide information from outside the body

interoceptors

provide information from inside the body

noise

nonessential information