物体和力（Objects and forces）.docVIP

物体和力（Objects and forces） The third chapter, movement and force Section 3.1 integral method and isolating method I. applicable conditions: generally used in systems where objects remain relatively static (not absolute). Two, the integral method and the isolation method are usually used together Example 1. Under the action of force F, the object M and M do the uniformly accelerated rectilinear motion, and then try to find out the forces acting between M and m in the following cases. (1) (2) (3); Muon =0 The Mu = 0, and m, M and the same. N=mF/ (M+m) Example 2. As shown, the quality of M is done on the rough level table of a car of M quality. People with horizontal force around a fixed pulley string, people and vehicles with the same acceleration on a smooth horizontal ground moving right, try to analyze the friction between M and m, F M and M the size of what? Solution: for whole: 2T= (M+m) a Yes, T+f=ma So: f= (m-M) T/ (M+m) Example 3. In one rope, two small balls of different quality are connected in series A B C D Three, the composition of the system of objects can not remain relatively static, and sometimes can use the whole method, and sometimes can only use isolation method. Example 4, as shown in the figure, the object of mass m, along the slope of the alpha mass of M slope, to accelerate the acceleration of a glide, the slope is still on the rough horizontal plane, and ask: M force. Example 5, pulley block model: Assignment: 1, in the horizontal plane on the two were 2 kg and 3kg iron m and M, among them with the original length of 10 cm, the stiffness coefficient for light spring 100 N / m with dynamic friction coefficient between the iron and the level was 0.2. M is a block size of 20 N constant horizontal force F, two blocks together to linear acceleration, as shown in figure. The spring length should be between two blocks (10 m / g gravity acceleration (S2)) A.12 cm B.13 cm C.15 cm D.18 cm 2 pulley block model. Section 3.2 program method Procedural law: a