Cross Product 一問

maxycy

Cross Product同Dot Product有咩唔同
我睇左本書幾次都唔係幾明=__=

[S]【YU】

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

[S]Mangoray

work done 好特別
F = vector
s = vector
乘埋就變左scalar

maxycy

岩岩無耐前自己明白左囉
依家見到有人答-3-
anyway
thx a lot

-終場ソ使者-

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-.-

[S]【YU】

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

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