外力的英文：
outside force
external force

参考例句：

Fluid motion caused by an external force such as gravity.
由重力等外力引起的流体运动.

To topple,as from power or a high position;fall.
下跌因外力或从高处倒下;倒下

It often takes trouble from outside to weld a family together.
要使一个家庭重归于好，往往需要求助于外力。

" It disrupts the ligaments, muscles, and capsule (encasing membrane) holding the joint in place."
外力的强度大于保持关节稳固的韧带、肌肉和关节囊的抵抗力时便能使关节脱臼。

force是什么意思：
n. 军队，暴力
v. 强迫，用力推动

by (main) force
用蛮力, 全靠气力; 以最大的力气

The force is spectacular!
这个瀑布很壮观！

resultant force
合力

The threat will force greater dispersion of their forces.
恫吓将迫使他们把兵力铺得更广。

The tension force, shear forces (including pushing force, cutting force and friction force), impulse force, hydrodynamic drag on the suction pipes, and the force resulted from the pressure difference, etc, are the main forces for detail discussion in this paper.
详细讨论了主要作用力：在波浪补偿器作用下的缆绳拉力、耙头与海床间的土壤剪切力、作用在耙吸管上的水流阻力及由于压力差在耙头处产生的推动力等。

external是什么意思：
adj. 外面的，外部的；外国的；对外的；表面的；外用的
n. 外面，外部

external ordering
外次序

There must be externally moderated tests.
一定要有外聘人员负责审核评分的考试。

Language externalizes thought.
语言使思想具体化。

The medicine is for external, not for internal.
这药是外用的，不是内用的。

The external of the building is very attractive.
这座建筑物的外观是很吸引人的。