http://postimg.org/image/47aygl3nx/
請高手指點 最好有步驟 唔該曬~
求指教 請高手指點
2014-10-16 4:13 am
回答 (1)
2014-10-16 3:04 pm
✔ 最佳答案
Let point (2,1) be A and point (5,2) be B.So vector OA is 2i + j and vector OB is 5i + 2j. (O is the origin).
(a) Displacement vector = vector AB = OB - OA = (5i + 2j) - (2i + j) = 3i + j.
(b) Force = 3i + 5j
So work done = Force dot Displacement
= (3i + 5j) dot (3i + j) = 3 x 3 + 5 x 1 = 9 + 5 = 14.
收錄日期: 2021-04-24 23:28:21
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20141015000051KK00107