Dynarnics 2. D Alembert's principle for a particle The mass of an unfree particle M is m. It is 、M O subjected to a positive force F.The reaction for a isN. The resultant force isR=F+N=ma f+N-ma=0 F+N+0=0 This is d, Alembert’s principle for a particle
11 The mass of an unfree particle M is m. It is subjected to a positive force .The reaction force is . The resultant force is . F N R = F + N = ma F + N −ma = 0 F + N +Q = 0 This is D’Alembert’s principle for a particle. 2. D’Alembert’s principle for a particle
学 二、质点的达朗伯原理 非自由质点M,质量m,受主动力F,x一F 约束反力N,合力R=F+N=ma a F+N-ma=o F+N+0=0 质点的达朗伯原理 12
12 非自由质点M，质量m，受主动力 ， 约束反力 ，合力 F N R = F + N = ma F + N −ma = 0 F + N +Q = 0 质点的达朗伯原理 二、质点的达朗伯原理
Dynamic This equation is an equilibrium form of a dynamical problem, it does not change the essential of the problems. The most outstanding advantage of the dynamic-static method is that the methods of statics can be applied to solve dynamical problems 13
13 This equation is an equilibrium form of a dynamical problem, it does not change the essential of the problems. The most outstanding advantage of the dynamic-static method is that the methods of statics can be applied to solve dynamical problems
学 该方程对动力学问题来说只是形式上的平衡,并没有 改变动力学问题的实质。采用动静法解决动力学问题的最 大优点,可以利用静力学提供的解题方法,给动力学问题 一种统一的解题格式
14 该方程对动力学问题来说只是形式上的平衡，并没有 改变动力学问题的实质。采用动静法解决动力学问题的最 大优点，可以利用静力学提供的解题方法，给动力学问题 一种统一的解题格式
Dynarnics EXample 1 a train is running along a horizontal railway, and a single pendulum is hanging in the carriage. When the carriage moves to the right with an uniform acceleration, the single pendulum will turn to the left by an angle as and does not move relative to the carriage Determine the acceleration of the carriage a 15
15 [Example 1] A train is running along a horizontal railway, and a single pendulum is hanging in the carriage. When the carriage moves to the right with an uniform acceleration, the single pendulum will turn to the left by an angle , and does not move relative to the carriage. Determine the acceleration of the carriage . a