在力平衡问题中，有一类通过物体的运动，绳子、斜面倾角的改变而使作用于物体上的各力发生变化，但物体仍受力平衡的问题，我们称之为动态力平衡问题．由于这类问题中涉及的力是变力，是动态力，力的大小和方向均要发生变化，要用动态思维来考虑这类问题，解题的思维能力层次 In the problem of force balance, there is a type of change in the inclination of the rope and the inclined surface caused by the movement of the object, so that the forces acting on the object change, but the object is still subject to force balance. We call it the dynamic force balance problem. Since the forces involved in this type of problem are variable forces and dynamic forces, the magnitude and direction of force must be changed. Dynamic thinking should be used to consider such issues and the problem-solving level of thinking must be considered.