圆盘滚动的有关问题经常在数学竞赛中见到 ,那么 ,圆盘滚动有何规律呢 ?1　圆盘沿直线滚动我们知道 ,圆盘沿直线滚动 ,其圆心移动的路程等于圆盘周长时 ,圆盘正好自转一周 ,如图 1 ,即当OO1 =⊙O的周长时 ,⊙O自转一周 .图 1　　　　　　　　图 2问题 1　凸四边形ABCD的周长等 The problem of disc rolling is often seen in the mathematical competition. Then, what is the law of the disc rolling? 1 The disc is rolling along a straight line. We know that the disc is rolling along a straight line, and its center of travel is equal to the disc circumference, the circle The disk rotates exactly one week, as shown in Fig. 1. That is, when OO1 = 周O’s circumference, ⊙O rotates one rotation. Fig. 1 Fig. 2 Problem 1 The perimeter of convex quadrilateral ABCD, etc.