等效力系
equivalent force system
equivalent force systems
equivalent forces
force system of equal effect
Equipollent
惯性力系
inertial force system
inertial force department
华北电力大学动力系
north china electric power university
空间力系平衡原理
Principle of equilibrium of three dimensional force system
空间平行力系
special parallel force system
空间任意力系
spatial arbitrary force system
空间一般力系
general space force system
力系的简化
reduction of force system
力系的约化
reduction of force system
内蒙古工业大学电力学院动力系
inner mongolia polytechnic university
electric power institute