Modeling and simulation are prerequisite to analysis and design of engineering systems. Modern engineering systems often are multy disciplinary, i.e., may include blocks from different majors of engineering, such as electrical, mechanical, fluid, etc. Availability of a unified approach for system modeling will make it easy for engineers or researcher from a certain discipline to model the systems from other disciplines. For example, with availability of a unified modeling methodology an electrical engineer will be able to model a system composed of electrical, mechanical and fluid systems. Modeling of complex mechanical systems is not always easy for engineers from other disciplines. On the other hand, it is much easier to establish mathematical model of electric circuits. Furthermore, simulation software is much richer for electric circuits. Therefore, in this paper a methodology is proposed for unifying the modeling of electrical and complex mechanical systems by obtaining electric circuit model of complex mechanic systems. In developing the proposed methodology, analogy between the electrical and mechanical elements have been used as tools. Proposed methodology has been applied to modeling and simulation of a relatively complex mechanical system and benefits accrued from this approach has been discussed. It is further proposed that the approach presented in this paper can be easily extended to modeling of dynamic systems from other engineering disciplines.