For measuring rotary acceleration this material can be in the form of a disk, for linear acceleration it is formed as a strip of metal (see picture on top).
旋转加速度测量这种材料可以在一个磁盘的形式，线性加速把它当作金属带组成(见上面图片)。
2
The second picture: the lid was covered well, there isn't a gap between the edge of the lid and the first strong strip of the pail.