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Benvenuti al più ampio studio sulle cadute in arrampicata
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Negli ultimi due anni abbiamo
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misurato e analizzato centinaia di cadute
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Grandi, piccole, con arrampicatori pesanti e leggeri
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e un sacco di attrito
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"Non riesco a fare sicura dinamica così!"
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All'inizio avevo due domante principali
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a cui volevo rispondere
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in questo studio; la prima è
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la quantità di lasco incide sulla caduta?
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Se l'assicuratore dà più corda, ovviamente
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l'arrampicatore farà una caduta più lunga, e se
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cadrà verticalmente la caduta sarà
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più dura perché cadrà di più.
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Tuttavia, nell'arrampicata si verifica spesso
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un piccolo pendolo, una piccola oscillazione
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verso la parete, quindi la domanda è:
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cadere di più riduce questo pendolo?
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Riduce la forza dell'impatto con il quale l'arrampicatore
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colpirà la parete? E la seconda parte dello
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studio cerca di rispondere alla domanda
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"qual è il miglior metodo per assicurare?"
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Compareremo il saltare in alto con
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il fare un passo avanti, e come bonus se cambia
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if the blayer is heavier and as an extra
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bonus we also compared against the tube
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style soft catches where you let the
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Rope slide through the device and while
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my curiosity started with these two
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questions I actually discovered way more
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including some peculiar cases how
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lightweight blayer can cause harder
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catch when a heavier
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blay so let's begin now the problem of
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making such studies is a sheer number of
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variables every fall is different we
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have different weights of the climber
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and the Blair the position of the
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climber before the fall fall height and
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the friction and also the Rope might get
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stiffer over multiple fs and of course
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the big one is how the Blair will handle
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the catch so so I thought okay challenge
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accepted I'm going to put a force
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measuring device on the climber and do
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as many different faults as needed to
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see the patterns and off we went
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measuring and measuring and measuring
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hundred hundreds of Falls and I was
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building a huge database of
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results and after a lot of work I
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understood something and oh [ __ ] moment
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happened what we were actually measuring
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was the peak Force to the climber's
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harness which happens around this moment
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of the Fall however this moment is not a
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problem for the climber what is the
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problem however is how hard the climber
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will hit the wall I always felt sorry
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for these lightweight climbers who are
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slammed into the walls and end up with
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broken or sprained
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ankles so let's fix that now while the
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peak forces should have a correlation
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with how hard the climber will hit the
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wall I needed to find a way to prove it
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and here I was mounting a camera to the
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wall with the hope to calculate the
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speed at which the climber would hit the
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wall based on slow motion footage and
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here was a tricky part due to
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perspective Distortion objects that are
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further away look smaller and in
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addition to that every camera lens
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introduced extra Distortion so I really
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needed to mount the camera as
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perpendicular to the climber's falling
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plane as possible and it's not like I
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can just float the camera anywhere in
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space I want but after a bit of root
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searching and then a lot of object
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tracking combined with a lot of custom
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code I wrote I got these beautiful
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velocity and acceleration
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graphs and now we can do hundreds of
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more fults and make sense of them all
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right let's begin with the question how
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does different amount of slack affect
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the fall what we did was a series of
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incremental Falls where the Blair does
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nothing basically causing a hard catch
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the first fall was with zero slack and
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even though it's a small fall I was
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swung towards the wall really
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hard for the second fall we used about
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half of arm of slack and despite the
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fall being a little bit bigger this time
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the peak horizontal velocity was
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lower now of course on such overhanging
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routes the more the Climber Falls the
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further the wall gets and that's why I
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was measuring horizontal speed and the
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peak of that speed usually happens at
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the bottom of the pendulum and it's a
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very good indicator of what would happen
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if the wall would not be overhanging all
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right let's try with even bigger Falls
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Charlie was clearly enjoying this yeah
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subscribe and the result was interesting
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the horizontal speed was nearly
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identical to the previous fall however
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the peak acceleration was bigger which
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means that the climber would reach the
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peak speed faster so based on this it
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seems that having a little bit of slack
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was better than no slack but having even
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more was
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questionable however despite us trying
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to Mim Mig hard catches these faults
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weren't that hard The Faults were
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relatively small and the blayer was
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still pulled up a lot and the reason I'm
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saying this is that in the past I have
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done similar tests under this bridge
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where I have discovered that once the
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fall is hard enough it exceeds the
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rope's ability to absorb the impact and
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the climber experiences a bounce back
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effect and this causes harder false for
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the climber however when we tried the
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same with soft catches there was no
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bounce back and the swing was
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lower so back to real Rock let's leave
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the hard catches for the reference and
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see how the soft catches will compare
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starting with zero slack we can see that
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the trajectory of the Fall is more
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gradual and that the horizontal speed
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and acceleration was lower significantly
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lower next fall was with half arm of
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slack and despite the climber falling
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more horizontal speed was actually
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almost
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identical so let's try bigger okay
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one two oh okay let's
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go o that was soft don't you think I I
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was too scared to think so despite
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nearly pulling my Blair into the first
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bolt and colliding with him the
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horizontal speed again was nearly
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identical so at least in this test case
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scenario falling more combined with soft
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catch had no benefits but as they say
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one test is no test and that's why I was
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rigging another one in the spot where we
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will be able to do even bigger Falls
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falling hardish so we started with zero
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amount of slack and Charlie giving the
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softest catch he can however the fall
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was described as hard
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dish
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ready yeah one two three
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falling softer and this time adding a
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little bit of slack felt softer for the
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climber and also did reduce the
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horizontal speed by a little bit so
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let's see what happens with even bigger
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Falls you good whenever you want one two
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three
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falling take a big pop very soft very
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soft and if we look into the graphs the
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horizontal speed was even lower this
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time so we went even bigger to 1 and 1
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half M of slack which is quite a lot one
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two three
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falling
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woo that was soft but there was this
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kind of D yeah yeah I I noticed it
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myself so this time the climber felt
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more jerk on the initial impact of the
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Rope however the horizontal speed was
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further reduced and looking into all of
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these faults we can clearly see
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correlation how increasing the amount of
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slack decrease reles the horizontal
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speed into the
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wall and since that was contradicting
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with our previous findings we had to do
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more Falls and in this scenario falling
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more was also better you can even see
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the visual
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difference and here is one more example
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this time the climber was falling from
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lower position and we had less friction
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once again falling more had softer
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impact with the wall so a summary of
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this segment is that the swing or the
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pendulum into the wall can be reduced by
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extra slack however if you exceed R's
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ability to absorb the impact the Rope
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will bounce the climber back into the
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wall and then things might be even worse
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and obviously falling more gets you
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closer to exceeding that limit but more
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importantly hard catch can get you there
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very quickly so for example here is one
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of the most common mistakes where the
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bler simply throws a ton of slack but no
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effort in making a soft
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catch
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okay and here is another one first a
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soft
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catch and now a hard one
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that okay we had the same amount of
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slack but the difference was
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massive you can clearly see the
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bounceback effect how the climber is
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being pulled back
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up what was your
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impressions one elbow versus two elbows
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versus three elbows no elbows between
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one elbow and two you'll have to measure
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that mass masso menos more or less what
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it's going to be but I think that's The
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Sweet Spot how was no slack at all
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difficult to give the soft catch it's
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difficult to give the soft catch yeah
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with no slag is really hard
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to hit the timing perfectly yeah so what
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we all noticed is that with zero slack
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it's really hard to give a soft catch
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because you don't have enough time to go
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down and jump up maybe with the
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exception If the fall is really big then
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the climber is falling for quite a while
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and then you have time but on very very
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small Falls you would have to have some
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cat reflexes and go like super fast but
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in general the most comfortable was
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between half to full arm of slack and
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that caused the softest catches for the
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climbers and more than that is very very
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rarely beneficial and simp simply asking
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for some collisions or dragging the
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blayer into the first bolt or simply a
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bunch of extra Pull-Ups for the climber
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after the fall and uh the bigger ones
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like three elbows like I say between one
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and two elbows is The Sweet Spot like
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one and two is more or less the same for
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me personally three is also softer Anna
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says but just a little bit harder to
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judge again but it's harder to judge
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when to jump mhm the EAS the climber is
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falling faster already exactly exactly
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now I can see how lightweight blers are
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probably already typing no slack for me
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I fly up anyway so we actually did
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testing on that and we got some
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interesting results but before that I
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just wanted to quickly say thank you for
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all my friends and supporters who helped
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in creating all of this study it's been
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the biggest project I've ever tried both
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in terms of time and energy and money so
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it would definitely not be possible
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without all of you so huge thank you and
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now back to lightweight blers so we
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started with zero
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slack wa that looked
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harder yeah visually and we can already
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see something interesting once the robe
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gets tight the speed of the climber
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starts to drop however as soon as the
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blay is pulled off the ground the speed
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of the climber starts to increase again
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the climber experiences a double fall
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effect okay let's increase the amount of
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slack we still get this double fall
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effect but the horizontal speed is
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reduced so let's go
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bigger and here we have the same pattern
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a double fall but the horizontal speed
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is even further
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reduced so let's try even bigger with
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crazy one and a half arms of
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slack you ready yeah three two one soft
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catch and here the double fall effect is
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very visible but same as in previous
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experiments we see a strong correlation
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that the bigger the fall the slower the
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horizontal speed for the climber so the
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softer impact with the wall and while
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that wasn't a surprise what was however
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a surprise is when we swapped her and me
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naturally I was expecting that the
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heavier Blair should cause a harder
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catch for the climber but if we compare
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Anna's no slack versus mine you can see
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that my catch was significantly
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softer
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and here is Anna's half arm of slack
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compared to
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mine and same results my catch was
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softer again and to be fair we were
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asking her to give a soft catch
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one two and give a soft catch you ready
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yeah soft catch on three 2
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1 and finally Anna's full arm of
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slack versus
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mine and to my surprise I was giving
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softer catches for the climber than the
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lighter
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belayer however I think this has more to
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do with the fact that lighter blers
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usually fly up anyway so they don't have
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enough practice to give soft catches but
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let me give you another example so this
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experiment was slightly different 118
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here Me and Charlie did a bunch of soft
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catches but this time we measured the
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forces to the climber this was the
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average line of Charlie's catches this
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was mine and this was the average of
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averages and we also did some hard
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catches for the
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reference that was much harder all right
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and now let's compare this to a light
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Blair no no and the first catch was
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really bad in fact as hard as our heart
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catches you jumped way too soon you've
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got to wait till she sucks you you're
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down here and when you can feel her
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sucking you you push up with
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her look at her once she starts falling
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you go down up I am getting scared
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come
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on no now the second catch was much
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better but still not what we were
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expecting so we did some
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practicing oh that was super soft
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falling and then this
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happened
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that look quite nice 12
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121 so as you can see experience plays a
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bigger role than being lighter and
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although lighter blares very rarely
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cause hard catches for
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climbers however with enough friction
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light Blair becomes heavy and actually
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recently I saw one really nasty fall
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where a bler was a light girl a climber
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was relatively light girl a lot of
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friction and a huge slam into the wall
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and then a poor girl had to get
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assistance to get back to the
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car and I'm curious did you ever got
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unexpectedly hard catch from a light
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blayer write down in the comments I want
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to see how often that happens all right
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so we have seen how both slack and soft
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catch has a big effect on the fall but
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there is something even more important
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here is a hard catch with no
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slack and here is a soft catch with a
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little bit of slack so we can see the
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best and the worst case
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scenarios but now check what happens
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when the Climber Falls from slightly
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different position I simply changed my
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legs but I was not pushing away from the
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wall
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[Music]
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[Laughter]
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[Music]
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I anticipa a bit too much there that's
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why you wear a
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helmet that would have been a what was
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it a trip straight to the yard a trip
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straight to the yard that would be
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go but if we look into the graphs we can
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see that this new fall
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had harder fall than the hard catch
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before despite Charlie trying to give it
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a soft catch with his
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head so as you can see how the Climber
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Falls can be more important than the
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amount of slack or a soft catch and here
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sometimes you can see beginners pushing
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away from the wall during the fall and
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combine that with another inexperienced
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delayer and a hard catch and that's a
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good recipe for sprained ankles so so do
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not push it's very rarely beneficial to
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push away unless you're clearing some
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kind of slab but otherwise do not push
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now in the second part of this study I
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wanted to figure out which blay method
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is the best so we compared jumping up
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versus stepping forward and also does
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that change if the player is heavier or
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there is a lot of friction in the system
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but since all of this is already SL slly
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different topic I'm going to split all
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of this in a part two of this video but
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before you go I wanted to share
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something with you that you might find
-
beneficial in order to create these nice
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charts that you have seen in this video
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I needed to understand how to take my
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messy experimental data and perform a
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polom fitting this allows to obtain a
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smooth graph that don't lose important
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points and chances are if you're like me
-
math and physics might not be our main
-
career path and our abilities to
-
understand such topics either never
-
existed or are already fading away since
-
the last time we sat in calculus or
-
physics class and that's why I've been
-
really enjoying brilliant.org it's the
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you curious human for watching my mega
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researches see you in the next one