3650 final Flashcards
4 components of vectors
magnitude
direction
point of application
line of action
mass
quantity of matter in a body
weight
gravitational force exerted on the mass of a body
forces
push/pull that tends to alter the motion state of a body
3 types of forces
mechanical
gravitational
frictional
displacement
length of the straight line joining the start and finish point with some sense of direction
sign of displacement
relative direction
velocity
how quickly is displacement changing in time
sign for velocity
displacement change relative to origin, pos away, neg towards
uniform displacement
contant velocity
we sample more frequenly for
more accurrate reps
what is biomechanmics
anatomy, physiology and the behaviour of living things interacting with engineering which are principes of physics applied to matter
model
accurate rep with reduced validity
detail specs of critical parameters
logical simplification for additional parameters
how to observe the behavior of biology and tissues (3)
observe and model it according to terms and techniques
- purpose - supportive motion/proprioceptive info
give diff treatments in diff situations to see change in behaviour
Tinbergen
behavioural problems according to time and benefit
current proximate
causation - hormones causing changes
current ultimate
function - what does it give you
historical proximate
development - change one generation
historical ultimate
evolution - change over many generations
qualitative
visual observation
quantitative
measurements from records
causative progression 2
mechanical quantities and constructed completely from lower factors
chronological progression 4
when to do tat
what’s working and what isnt
decrease in factors
antecedent - behaviour - consequence
consequences could be
full or half ecological behaviours - targetting vs hitting
body referenced system
egocentric - focused on behaviour
world referenced system
allocentric - time based
muscle forces
larger than load and joint forces were even larger
vectors
physical parameters that can only be fully represeneted through magnitude and direction
distance
scalar - #
displacement
vector - # and direction (global point of application and line of action)
how to sum vectors
tip to tail
when 2 forces added up are more than the resultant vector
some forces being wasted because the line of action is not in desired direction of movement
fornix
the part of your brain that always adds tip to tail
fy
perpendicular to the midline of segment and rotates it
fx
paralll to midline of segment and either stabilizes or dislocates it
body
solid object with a multidimentional volume that contains a stable amt of matter
state
condition matter is in
state of motion
movement condition that matter is in
acceleration
how quickly is velocity changing in time
sign of acceleratoin
pos accelerate, neg decelerate
w
mg
equal change in velocity in equal change in time
uniform acceleration
displacement on a AT graph
area under curve
longer strides
less steps, lower frequency and increased efficienct
gravitation law
always pulls an object directly toward earth - all bodies attract one another with a force proportional to the product of their masses and inversely proportional to the squre of the distance between them
forensic biomechanics
exert scientific knowledge to legal problems
biomechanical plausibility
forces from event imposed on anatomical region are efficiently high enough to exceed the tolerance limits of that region
fluids
gas, liquids and solids - phases of matter
gas
molecular proximity defined by container
dynamic fluid forces
lift and drag
static fluid forces and what they are determined by
pressure and buoyancy - position, size, structure
buoyancy
supportive force produced by orderly displacement of fluid molecules that are absent initially until fluid rearranges itself
if youre less dense
more buoyant
density
mass/bolume
more volume
more buoyant
sum of the forces in the y direction of an object in the tank and which are determined by the volume
- pressure, - weight and pos buoyancy - pressure and buoyancy
drag and 4 factors
resistive force that results from collisions with fluid molecules obejct cross section fluid density object velocity fluid flow parameters
surface drag
friction - slows down the boundry layer
formed drag
resistance - pressure differential between lead and rear sides which is high in the front and low in the back
laminar flow range 1
smooth surface, low velocity, high surface drag
laminar flow
straight layers
high surface drag
attract fluid molecules to it
partially turbulent flow range 1
some formed drag
less surface drag
turbulent low pressure wake in the back with disorganized flow and decreases support of fluid force from behind
partially turbulent flow range 2
higher velocity, more formed drag, little surface drag
pressure wake in the back
seperation of boundary layers
why rougher surface
no form drag, fuller boundary layer to be less turbulent and more surface drag, turbulent flow (full) - keep the support in the back
diff surface collison
deflection - gear effect - keeps on bending
lift
supportive force produced by relative pressure on opposite sides of an object
magnus effect
low velocity and high pressure on top and high velocity and low pressure on the bottom - surface drag travels in diff directions - boundary layer of air spining with the balls surface
airfoil
low pressure and high v on top, high p and low v at the bottom, (becasuse all air pockets will finish at the same time - lifts it up
