Cross Product 一問
Cross Product同Dot Product有咩唔同我睇左本書幾次都唔係幾明=__= dot product 係搵scalar product
e.g. work done = F.s
cross product (a x b)係搵 vector product (prependuclar to a-b plane)
e.g. right hand rule,FBI o個3支野
F = B x I work done 好特別
F = vector
s = vector
乘埋就變左scalar 岩岩無耐前自己明白左囉
依家見到有人答-3-
anyway
thx a lot 不過用邏輯都諗到W唔會-ve,你唔會推動一樣野反而又得到1D WORK架嘛-.- 不過用邏輯都諗到W唔會-ve,你唔會推動一樣野反而又得到1D WORK架嘛-.-
-終場ソ使者- 發表於 28-8-2010 15:07 http://www4.nakuz.com/bbs/images/common/back.gif
咁你既邏輯似乎有點問題....
假設你同另一個人鬥推,唔夠力,俾佢推返轉頭,呢個case就係-ve work done.
Force向前,但displacement向後: F x -s = -WD
頁:
[1]