Kinetics is the science that studies movement: how things move, and what makes them speed up, slow down, or change direction.

Kinetics isKinetics是 the science that studies movement研究運動的科學：how things move東西怎麼移動，and what makes them speed up, slow down, or change direction以及是什麼讓它加速、減速，或改變方向。

In physics it sits beside kinematics — though actually the tidy textbook split is tidier than talk in class. Kinematics often means describing the motion (path, speed); kinetics, close to dynamics, asks about the forces.

In physics在物理學裡 it sits beside它跟 kinematics（運動學）並列——though actually不過其實 the tidy textbook split is tidier than talk in class課本上分得那麼整齊，課堂上講起來沒那麼乾淨俐落。Kinematics often meanskinematics通常指 describing the motion (path, speed)描述運動本身（路徑、速度）；kinetics, close to dynamicskinetics則比較接近dynamics，asks about the forces關心的是背後的力。

In chemistry, chemical kinetics is the study of how fast reactions happen and what changes the speed — heat, a catalyst, how much of each chemical you mix. Taiwan schoolbooks often print 動力學 for both the physics and the chemistry use, so the English word is doing more than one job.

In chemistry在化學裡，chemical kineticschemical kinetics is the study of研究的是 how fast reactions happen and what changes the speed反應多快發生，以及什麼會改變速度——heat, a catalyst, how much of each chemical you mix熱、催化劑，還有你混合了多少各種化學物質。Taiwan schoolbooks often print台灣課本常把 動力學 for both the physics and the chemistry use印成物理和化學這兩個用法，so the English word is doing more than one job所以這個英文字其實身兼多職。

It looks plural (it ends in -s) but as a subject name you usually treat it as singular, like physics: “Kinetics is…” not “Kinetics are…”.

It looks plural這個字看起來是複數 (it ends in -s)（字尾有-s），but as a subject name但當成學科名稱時 you usually treat it as singular通常當單數用，like physics就像physics一樣："Kinetics is…" not "Kinetics are…"要說'Kinetics is…'，不是'Kinetics are…'。