万有引力定律部分内容比较抽象,习题类型较多,不少学生做这部分习题有一种惧怕感,找不着切入点.实际上,只要掌握了每一类习题的解题技巧,困难就迎刃而解了.下面就本章的不同类型习题的解法作以归类分析.一、求天体的质量(或密度)1.根据天体表面上物体的重力近似等于物体所受的万有引力,由天体表面上的重力加速度和天体的半径求天体的质量由 mg=G Mm/R~2得 M=R~2g/G.(式中 M、g、R 分别表示天体的质量、天体表面的重力加速度和天体的半径.) Part of the law of universal gravitation is more abstract, more types of exercises, many students do this part of the exercises have a sense of fear, can not find entry point.In fact, as long as each type of problem-solving skills to solve the problem, the difficulty is solved. First, find the mass (or density) of the celestial body 1. According to the gravitational force of the object on the surface of the celestial body is approximately equal to the gravitation of the object, the acceleration of gravity and the celestial body The mass of celestial body is M = R ~ 2g / G from mg = G Mm / R ~ 2, where M, g and R denote the mass of celestial body, the gravitational acceleration of celestial body and the radius of celestial body, respectively.