Kinetics (M2) Flashcards by Charlotte Parker

what is torque influence by

magnitude of the force
direction
point of application of force

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what is the equation for torque

T=Fr

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when the sum of all torque acting on a joint are equal to 0 what does this mean

static at point of equilibrium - balance

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what is the equation for bending moment

M=Fx
(force applied to the beam multiple by distance)

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anti clockise is what direaction for right hand rule

positive

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to accelerate an object what things do you need to have angular rotation

force applied off centre
torque

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what is the formular for mass moment of inertia

I= mr^2

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what does mass moment of inertia only explain

how difficult or easy a movement may be considering the distribution of mass about the axis of rotation

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who is more likely to have more momentum - beaudan barrett or sam whitlock. some one that has more mass or less mass, when travelling at the same speed

Sam whitelock - someone that has more momentum

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what is the formular for angular velocity

H= mr^2*w

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what 3 things affect angular momentum

Mass
1. Distribution of mass with respect to axis of rotation
Angular velocity of body

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Why is total momentum system conserved during angular rotation in the air

gravity acts through the CoM, therefore doesn’t cause momentum

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T/f angular momentum can be transferred from one axis of rotation to another

true

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how does a long jumper is able to stray up right, because when they take of they have a forward momentum that courses them to rotate forwards

Transfer of moment from com to the limbs (rotate) so body stays up right

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how do we alter the axis of rotation in the air

make axis off centre (so it doesn’t go through Centre of mass) e.g. have one arm up

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what is the resistance of a body to rotate called

mass moment of inertia

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how does an athlete generate angular rotation

by applying a rotational force to the body

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during running when do you reach peak velocity

in max velocity phase
when acceleration is 0

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what are the 4 phases of running

drive
transition
max velocity
maintainece

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what makes a good runner (usain bolt)

able to hold max velocity for longer

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what is the term radius of gyration

when dealling with segment of masses where axis of rotation is not located through the centre of mass

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what is the concept of work

use force to move an object

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how do you calculate work

W=F*s(cos(theta))

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what is the concept of power

P=Work/time

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Power is limited by the rate of what

ATP

what curve limits power

Force-velocity curve

why does it take longer to perform max rep

more muscles are need to move heavier weight, takes longer for them to contract

what can joint power determine

the product of net torque and the joint angular

when will power be positive - what are the signs for angular velocity and angular acceleration - what is this referred to

same power production

what does power production mean for energy flow direction

muscle to arm segment

power absorption mean for energy flow direction

arm segment to muscle

what is newtons first law

object will remain at rest or constant velocity unless external forces act on it

what is the equation for force - newtons 2nd law

F=ma

newtons 3rd law

for every action there is an equal to opposite reaction

what quantity is force

vector (has both magnitude and direaction)

what is the net force

sum of all force

what are the 5 steps to drawing a free body diagram

1. identify the system 2. separate the system 3. identify COM 4. identify external forces 5. find resultant of forces (by using pytha)

what does CoP (centre of pressure) mean

average pressure point beneath the foot or feet

what are the gait objectives

1. propel body forwards 2. efficiently - minimal energy expenditure

in the 1st peak of normal walking what should x the persons body weight

1.2

the 1st peak (F1) if this is lower what can it tell about the person

the are less confident or slower walker

in the trough what is the x to the persons body weight

0.6

in the trough (F2) if its deeper what does this signify

if they are moving quickly though movement

what does a low peak in the 2nd peak (F3) mean

individual has poor ability to propel their body forwards

what is the claw back

the initial spike in walking diagram - clawing toes into ground like a peginuin

what % of stance phase does cross over

55%

what 3 components is the resultant GRF made up of

1/ vertical 2. anterior -positor 3. medial -lateral

what do pedotti digrams rely on

information provided by the force plate

wht 3 things do you need to construct a pedotti diagram

1. vertical force 2. horizontal force 3. position of center of pressure

what is inertia

resistance to change motion state

what is the equation for momentum

L=Mx V

How do you maximise performance with anterior -posterior impulse (e.g. long jump

1. gaining initial momentum from run up 2. minimising loss of momentum - redirecting hz motion into vt motion

does a force through COM generate linear motion

yes

when force is not applied to the COM of the ball - what force does this create - what is this - what motion (linear or angular)

eccentric force torque linear and angular

what are three things torque is influenced by

1. magnitude 2. line of action 3. point of application

what is the equation for torque

T= Fr sin (theta)

what only causes rotation in - where the objects placed

perpendicular - therefore use sin because of it

with regards to the right hand rule if is clock wise is this positive or negative

negative

what makes a successful high jump

1. less mass 2. largest vt force

for the fosbury flop what must an athletes create rotation around

Centre of mass

what is the equation for angular acceleration

a= T/mr2

repositioning _____ can help to alter angular acceleration

limbs

having a greater mass does this make it easier or harder to change angular velocity

harder

what does mk2 mean

radius of gyration - remote terms e.g. mass x distance form COM^2

for a flexion extension graph every time there is a peak what does this mean for the for the velocity time curve

it will cross over the line of the velocity time curve

for a flexion extension graph every time this graph crosses the centre line what does this mean for the for the velocity time curve

change in direction for the velocity time curve

when velocity time curve has a peak what does this mean for the acceleration graph

will cross the centre line

every-time the velocity time graph crosses the centre line what does this mean for the acceleration graph

acceleration graph will have a peak

moment of inertia depends on what

axis of rotation

how do remote and local axis differ

remote = external local = own

what does mass moment of inertia not explain

speed or velocity

what is the equation for angular momentum

H=mr2 x w

what are three things that effect angular momentum

1. mass 2. distribution of mass with respect to rotation 3. angular velocity of the body

once airborne is it possbile for athlete to alter angular velocity by changing momentum of inertia

yes

when body rotating in air -momentum is what

conserved

why is momentum conserved in air

- no external forces gravity acting through COM

what is angular momentum the product of

moment of inertia and angular velocity

when do you reach peak velocity - when acceleration is what

acceleration zero

having a large spiek for accerlation curve in running is associated with what

quick explosive acceleration with high peak force - often seen in world class sprinters

explain the force in the medial-lateral direction during walking

- small anterior impulse - claw - this large posterior impulse - going below line - this around 50% through-stance phase increases anterior impulse (goes above line)

increasing to reach peak velocity - what happens to hz forces and - propulsive and breaking force

- Hz force begins to decrease - propulsive and breaking begin to equalize

object moves with sufficienctly high velocity relative to surrounding fluid, layers of fluid near surface of object mix and flow becomes turbulent of laminar

turbulent

viscosity involves _____ resistance of fluid to flow

internal

buoynacy forces act through what

centre of volume

what does the vertical force component for single step look like

M shaped

what is a special type of force diagram that is used in gait analysis

Butterfly force diagram

how do you calculate reaction force

sum of force: R - weight (9.81)

derive joint power time curve by multiplying angular velocity and angular acceleration together - what is this called

inverse dynamics

max velocity = what of KE

max KE

the net work done by all forces acting on the body equals the change in KE describes what theorem

Work-energy theorem

what contributes to the drag force

- surface friction - form drag - reduce negative pocket - wave drag - interface of 2 fluids

why is swimming an inefficient form of motion

deals with all three forms, more dense and viscus

what direction is lift force generated in with respect to fluid flow

perpendicular to fluid flow

explains Bernoulli's principal in terms of velocity and pressure

high velocity flow to low pressure

what is the magnus force

lift force created by spin

what is force locking

force locking between 2 smooth materials

what is form locking

material properties of traction

what are the three aspect that create a lift force

1. foil shape 2. angle attack 3. spin

how doe foil shape effect lift force

- fluid seperation, low pressure - high velcity over top

hoe does angle of attack effect lift force

angle of orrinetation - optimum angle of attack for maximizing range is angle at which lift/drag ration is maximum

what contributes to the drag force

- surface friction - form - reduce negative pocket - wave drag - interface of 2 fluids

what is the most important component of the drag force equation

velocity

what are ways swimmers can reduce drag forces

- streamlined positon as much as possible - head down - tight swim wear - swim cap - small surface area

what stroke style has the least amount of drag

freestyle

example the reverse swing

turbulent (rough side) faces the batsman. bowled fast enough (above 85mph). laminar side goes into turbulent befor reaches seam

what is Bernoulli's equation

P + 1/2mv^2 +pgh = constant

what is the equation for work energy theory and what is work transferred into

W=E2-E1

Kinetics (M2) Flashcards

(107 cards)