lecture 8 Flashcards
(22 cards)
what is projectile motion?
motion of objects under the influence of gravity and air resistance
why do longer jumpers adopt a piked position?
although the cg path cannot be later din flight, internal forces may be used to change the distribution of mass(position of segments) with respect to CG
does your body follow the same path regardless of how you change the position of body segments?
yes, once in the air you can not apply more force nor ca you change CG path.
what is the key technique for overcoming the hurdles?
lift less to needed height but bring trunk lower
what do you want to minis when you are overcoming hurdles?
time in the air
what factors influence projectile motion?
speed of release, height of release and the angle at which it is released at
what is the optimum angle for the maximum range?
when the release height and the landing height are the same, optimum angle is 45 degrees
when the release height is greater than the landing height…..
the optimal angle is less than 45 degrees
when the release height is smaller than the landing height?
the optimal angle is greater than 45 degrees
why is there no specific angle fro greater or less than for height?
because it depends on the height of release
what is drag?
acts in the direction of airflow, reduces speed of a projectile along its path
what is lift?
acts at right angel to drag helping the object to stay in the air for longer
examples of activities which rely on controlling lift?
discus and javelin throwers so that they will encounter a minimum amount of drag
what does lift do?
acts in right angles to drag and extends flight time
what happens when you neglect air resistance, what is projectile motion characterised by ?
projectile motion is characterised by content horizontal velocity but change in vertical velocity
regardless with what you do with your arms and legs, what follows the exact same path once in flight?
centre of mass
for a given peak of CG, lowering some parts of the body will….
make other parts go higher
what are some examples of goals of projection other than range?
maximising time in air
minimising time in aim
what is an example of maximising time in air in terms of projectile?
badminton, tennis
what is an example of minimising time in air in terms of projectile?
passes in team sports, cricket, soft ball, rounders
what does air resistance effect (projectile motion)?
the trajectory and range of projectiles
which activities rely on controlling lift and why?
discus and javelin throwers try to minimise amount of drag but at the same time maximise lift to extend there flight time in the air.
