CSIA新录像

jluo

why we don't want friction? why we want 0 pressure? can we do something else to achieve 0 pressure?

quoiguaski

jluo 发表于 2012-12-14 12:12
why we don't want friction? why we want 0 pressure? can we do something else to achieve 0 pressure?

• 对于新手来说怕弯转不过来，　对于你来说可以更牛Ｂ
  
• 对于新手来说怕弯转不过来，对于你来说可以更牛Ｂ
  
• Ｙｅｓ，　氢气球
  

xinxinqi

这个表演者怎么着也得是CSIA4级吧.
能看顺眼的至少得CSIA2级吧.
能看的滚瓜乱熟的怎么也得CSIA3级了.
反正我看的是心惊肉跳的.

jluo

from a pure physics point of view, most of our motions are based on friction/reaction forces, Ff=Fp*e, if Fp=0, Ff=0, then no force no motion ==> I am confused

jluo

umm, I think I might get it ... might ...

jluo

there are two forces, the friction along the axis of movement, and the force perpendicular to it, to support the body etc, if we take away the pressure, the weight/gravity would be cancelled by the normal force from the ground, and the force (created by engaging the edge) along the ground line .

if we assume the ground is perfectly rigid, so no energy loss due to skidding, the skis should bend into the shape of turn, combined with edging, that is how we turn, right?

jluo

xinxinqi 发表于 2012-12-14 12:20
这个表演者怎么着也得是CSIA4级吧.
能看顺眼的至少得CSIA2级吧.
能看的滚瓜乱熟的怎么也得CSIA3级了.

professor gua is above all this

quoiguaski

jluo 发表于 2012-12-14 12:38
professor gua is above all this

借刀杀人啊，这是

jluo

quoiguaski  normally, we talk force means that “Centrifugal force”，　so feel cool and pro...gravity is not a force, too naive

understood! centrifugal is part of the gravity. there is no such thing as 0 friction, but we can minimize friction by 0 pressure, aka net force

jluo

you can delete comments?!!!