An axis is a straight line around which an object rotates. Movement at the joint take place in a plane about an axis.
There are three axis of rotation. Sagital axis - passes horizontally from posterior to anterior and is formed by the intersection of the sagital and transverse planes.
solid of revolution 회전체
a solid of revolution is a solid figure obtained by rotating a plane curve around some straight line (the axis of revolution) that lies on the same plane.
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수학영어(Mathematics English)
arc : 호, '나무로 만든 활', 원주위의 두 점 사이의 부분
body of rotation : 회전체, 한 직선을 축으로 평면도형을 회전시킬 때 생기는 입체도형
capacity : 들이 (용기의 부피), 용적