The physics teacher now sets up a transverse wave on a long elasticcord by moving her hand up and down, as shown in the diagram below.
物理学教师现在让有弹性绳子的以横向波形式上下移动，如下面的图解中所示。
2
The quilt cover may utilize the elasticcord ring on its four corners and fixing buckles at both sides of mattress body, realize the anti-falling off effect.
防踢被盖是利用其四角上的松紧带环与垫体两侧的固定扣相连，实现防踢效果。
3
The principle of selecting cord with high tenacity and low elastic modulus was proposed.