用一扁钢t=30mm,圆心角90度圆弧,半径r=200mm,求下料长度.
问题描述：
用一扁钢t=30mm,圆心角90度圆弧,半径r=200mm,求下料长度.
答
l=314mm怎么求的？过程！l=αrα=π/2代入得l=314mm
用一扁钢t=30mm,圆心角90度圆弧,半径r=200mm,求下料长度.
l=314mm怎么求的？过程！l=αrα=π/2代入得l=314mm