The force of friction slows the spacecraft down as it re-enters the earth's atmosphere.

航天飞机重返地球大气层时因有摩擦力而减慢速度。

《牛津词典》

The frictional force remains constant, dependent on the friction, the kinetic friction coefficient, is always the same...

摩擦力不守恒，它取决于摩擦力，动能摩擦系数，一直是相同的。

youdao

The more rough and jagged something is, the more easily more of its molecules will come into contact with molecules on the surface it touches, and thus the greater force of friction they will exert.

物体表面越粗糙不平，它的分子就越容易更多地与接触表面的分子相粘合，因此就会产生更大的摩擦力。

youdao

That means the force you're applying is cancelled by another force, which has got to be the force of friction.

意味着你施加在物体上的力被另一个力抵消了,这个力就是摩擦力

耶鲁公开课 - 基础物理课程节选

So force of friction is yet another force.

摩擦力就是另外一种力

耶鲁公开课 - 基础物理课程节选

They worry about the growing power of the Sunni sheikhs within the police force, that could lead to more friction with the Shiite-dominated government in Baghdad.

NPR: Sunni Sheiks Join Iraqi Police to Fight Al Qaida

He had complained frequently that the Air Force was not getting ground forces the reconnaissance support they needed in overseas conflicts, and there was continuous friction over modernization priorities (Gates eventually terminated a fighter program championed by the purged Air Force leaders).

FORBES: Air Force Positions For Resurgence In Pacific Era