曲線面積的二次矩(慣性矩) - 土木
By Franklin
at 2013-12-16T14:57
at 2013-12-16T14:57
Table of Contents
題目：求x軸的慣性矩
http://farm8.staticflickr.com/7420/11398182013_374eae3198_c.jpg
答案：18
小弟的算法：
x = k*y^3
4 = k*27
k = 4/27 = 0.15
x = 0.15*y^3
y = 1.88*x^(1/3)
4
Ix =∫{[(1/2)*y]^2} * dA = ∫{[(1/2)*y]^2}*y*dx = ∫ [(1/4)*y^3]*dx
0
4 4
=∫ 1.66*x*dx = 0.83x^2 | = 13.28
0 0
小弟積分出來的結果為Ix = 13.28，但是答案為Ix = 18
請問版上前輩們，後學哪個地方計算錯誤，還是哪邊的觀念有問題呢？
麻煩不吝嗇指導與告知，謝謝！
--
Tags:
土木
All Comments
By Dora
at 2013-12-20T06:56
at 2013-12-20T06:56
By Irma
at 2013-12-23T20:00
at 2013-12-23T20:00
By Leila
at 2013-12-25T19:59
at 2013-12-25T19:59
By Rachel
at 2013-12-29T02:15
at 2013-12-29T02:15
By Michael
at 2014-01-02T04:38
at 2014-01-02T04:38
By Olive
at 2014-01-04T02:30
at 2014-01-04T02:30
By Bethany
at 2014-01-06T04:53
at 2014-01-06T04:53
By Lydia
at 2014-01-10T07:34
at 2014-01-10T07:34
By Joseph
at 2014-01-14T17:31
at 2014-01-14T17:31
By Connor
at 2014-01-19T08:55
at 2014-01-19T08:55
By Lauren
at 2014-01-20T15:30
at 2014-01-20T15:30
By Delia
at 2014-01-22T13:49
at 2014-01-22T13:49
By Leila
at 2014-01-24T00:57
at 2014-01-24T00:57
By Agnes
at 2014-01-27T01:47
at 2014-01-27T01:47
By Kyle
at 2014-01-29T09:29
at 2014-01-29T09:29
By Puput
at 2014-01-30T11:40
at 2014-01-30T11:40
By Todd Johnson
at 2014-02-03T12:41
at 2014-02-03T12:41
By Agnes
at 2014-02-06T07:20
at 2014-02-06T07:20
By Damian
at 2014-02-07T18:37
at 2014-02-07T18:37
By Erin
at 2014-02-11T01:11
at 2014-02-11T01:11
By Irma
at 2014-02-12T13:52
at 2014-02-12T13:52
By Charlotte
at 2014-02-17T04:43
at 2014-02-17T04:43
By Callum
at 2014-02-20T00:00
at 2014-02-20T00:00
By Ida
at 2014-02-24T22:33
at 2014-02-24T22:33
By Caitlin
at 2014-02-26T07:27
at 2014-02-26T07:27
Related Posts
急詢堆高機，明早北市去下貨3棧板
By Edward Lewis
at 2013-12-15T22:23
at 2013-12-15T22:23
請問這個圖要用什麼程式畫
By Puput
at 2013-12-14T21:52
at 2013-12-14T21:52
轉考環工
By Suhail Hany
at 2013-12-14T20:02
at 2013-12-14T20:02
一些力學問題
By Tracy
at 2013-12-14T16:59
at 2013-12-14T16:59
瀝青混凝土跳料嚴重
By Puput
at 2013-12-14T00:01
at 2013-12-14T00:01