Corso di sci Check Point 2019 - 09 Importante dislivello

Check Point 2019 - 09 Importante dislivello
Uno dei problemi più importanti é quello della tendenza ad arretrare, vediamo come risolverlo.
Per i corsi di sci: www.jam.it

[@tadeuszjastrzebski7791]

Thanks for English translation. Your ski academy is the best. Translate more often.

[@leonardomorganti1573]

Tutto vero!! ma e più facile spingere con le spalle dove c'è pendenza minore piste rosse oppure blu dove c'è pendenze superioriori non riesco e arretro... come nere ha mio parere serve molto allenamento sulla muscolatura è tutta quella che dà sicurezza. Bel video come sempre.

[@justyolivieri5807]

i tui dimostratori sciano tutti diversamente. Ce qui cambia diretto, quei cambia indiretto. Qui pasa approfittando la forza inerziale e qui se spinge. Sono in assoluto disaccordo con il tuo modo di spiegare como risolvere il problema.

[@jamsessionskiacademynetwork]

Ciao Justy, ci sono tanti modi per risolvere questo problema, quello che spiega Valerio e' uno dei tanti ed e' un concetto per noi importantissimo, che ci da molto risultato con gli allievi. Su cosa non sei d'accordo esattamente? Per te quale sarebbe il consiglio migliore?

[@jurijfranko9002]

Sorry, but explanations make no sense at all what if keeping COM backward is physical condition to keep dynamical equilibrium? Also term acceleration is used in some funny ways. Please keep your physics up to date (at least up to Isaac Newton).

[@paoloa102]

Hi Juruj, (I'm Paolo, Jam Session ski teacher)...I would like to understand your criticism...we said that in carving skiing, during the phase when the skis go towards the slope there is an acceleration and it is necessary to follow it with the body in order not to stay behind.....what do you think is wrong?

[@jurijfranko9002]

@@paoloa102 Hi. First of all, skis do not accelerate in direction of skis, skiers do, and only beause of gravity, not because of any other effect like 'rebound'... Acceleration id change of speed over time. According to Newton, ther must be a force paralel to speed to increase speed, oppoite do decrease and perpedicular to change direction of speed (movement). Position of CG (COM) over the length of the ski is a side efect of completly different problem. By moving CG backward skier increases torque of the ski (decreases edge grip of the tail) - how ski deforma under load is demonstrated here (vimeo.com/user46458921). In case a skier start a turn without enough rotational speed, the skis during skidding will not follow geometry of a turn, therefore skier must make a corection by moving CG backward (demonstration of rotation as function of CG position is vimeo.com/user46458921 wher you can see that loaded part of the ski actualy looses edge grip and produces torque as described above. To comment on your definition of acceleration (3:10) - You can look at acceleration also as increase in kinetic energy. The only way to increase energy is by convering potential enery to kinetic energy by gining down the slope and loosing as litle energy as possible to friction and air resistance. If you look at your video at 3:38 frame by frame you can see that a skier is making rotation without touching snow surface. There is no external force to produce a turn. As he lands again on the snow he has rotational speed and skis positioned at angle to direction of skiing. During a turn he has to stop rotating to avoid facing uphil, therefore he has to put his CG forward to produce torque to stop rotating. (uf, complicated) and start rotation in opposite direction for next turn. But in case ths skier at 3:38 would not be rotated as much as in above case, he would have to go with CG backward to get torque necessary to complete a turn.