式中r是圆周运动的半径,因此（In the formula, R is the radius of the circle motion, therefore）.doc

式中r是圆周运动的半径,因此（In the formula, R is the radius of the circle motion, therefore） Collected by oneself Mistakes are unavoidable For reference only In case of error Please correct me! Thank you Four, mechanical energy transformation and conservation law and their applications 1. potential energy The energy determined by the relative position of interacting objects and the nature of the interaction between them is called potential energy, depending on the nature of the interaction force between the objects It can be divided into gravitational potential energy, elastic potential energy, molecular potential energy, electric potential energy, nuclear potential energy and so on There are two kinds of potential energy encountered in Mechanics: gravitational potential energy and elastic potential energy 2. gravity potential energy When the object on earth is at a certain height, the energy is called gravitational potential energy, as shown in Figure 5-2 If the mass of the object is m The height from the ground is h Then the gravitational potential energy of an object can be expressed as Ep = MGH That is, the gravitational potential energy equal to the product of the gravity and the height of the object For gravity potential energy, the following points should be clearly defined: (1) gravitational potential energy is common to systems composed of objects and the earth The condition of gravitational potential energy is that the object must be under the weight of the earth otherwise There is no concept of gravitational potential energy, the gravitational potential energy of an object Just for convenience of narration (2) gravity potential energy is relative Only the location of the zero potential energy is determined The gravitational potential energy has a definite value. When the reference position is zero, the potential energy position is chosen The gravitational potential energy has different values. In formula Ep = MGH In fact, the ground has been chosen as the zero potenti