等效力系
equivalent forces
equivalent force system
equivalent force systems
force system of equal effect
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
内蒙古工业大学电力学院动力系
electric power institute
inner mongolia polytechnic university
平衡力系
balanced system of force
equilibrating force system
平面汇交力系
plane concurrent force system
plane converging system of forces