four force meaning in English

四维力
四元力

There are four forces which act on an aircraft as it flies through the air
飞机在空气中飞行时，有四个力作用在它身上。
The force laboratory is equipped with four force standard machines . the two smaller machines are deadweight machines of rated capacities of 5 kn and 60 kn respectively
其中两部较小的为静重式标准测力机，其额定力值分别为5kn和60kn 。
The four forces are co - ordinated ; if one of them is not strong enough , the rest will be affected . poor co - ordination will also harm the base area
这四种力量又是互相配合的，任何一部分不得力都会影响到其他部分，互相配合不好也会使根据地受到损害。
Firstly , the hertz contact theory is used to design the export moment of the prototype ; deformation status of the flexspine under the elliptical cam wave generator action is analyzed using the column shell theory , whose boundary condition is four force action . design proposal of the wave producer put forward considering the precision theory of rolling friction transmission
首先用赫兹接触理论对样机的输出力矩进行了设计;应用四力作用下的光滑圆柱壳体理论分析了在椭圆凸轮波发生器作用下柔轮的变形状况,结合滚动摩擦副传动精度理论提出了波发生器总体设计方案。