对于物理专业的学生，在修完普通物理後，还要系统的学习物理学的核心理论，也就是常被称为“四大力学”的物理通修课程。包括理论力学（有时候被称为  分析力学 ）、统计力学（也叫做热力学和统计物理）、电动力学和量子力学。这些理论是物理学中牢牢建立起来的基础理论。
Each ephemeris was produced by numerical integration of the equations of motion , starting from a set of initial conditions . Due to the precision of modern observational data , the  analytical method of general perturbations could no longer be applied to a high enough accuracy to adequately reproduce the observations . The method of special perturbations was applied , using numerical integration to solve the `` n '' -body problem , in effect putting the entire Solar System into motion in the computer 's memory , accounting for all relevant physical laws .
两词在上述语境中含义相同。