处于力学平衡位置的物体在受到小的碰触后很难恢复原来位置的平衡状态unstable equilibrium

• 西北黄土山脉地质结构不太好，处于不稳定平衡状态。

  The geological structure of the north-western loess mountain range is in a bad state of unstable equilibrium.

• 利用不稳定平衡原理，将门锁的锁闭状态设计成一种平衡模式

  use the principle of unstable equilibrium to design a door lock that is in a mode of equilibrium when locked