# Differences between these four branches of physics

1. I am wondering what are the main differences between these four branches of physics: Statics, Kinematics, Dynamics, and Kinetics?
2. And whether the following relationships are correct or not?

• Statics: there is no speed and there is no acceleration
• Kinematics: there is speed and there is no acceleration
• Dynamics: there is speed and there is acceleration
• Kinetics: there is speed and there is acceleration
• Possible duplicates: physics.stackexchange.com/q/1135/2451 , physics.stackexchange.com/q/27897/2451 and links therein. – Qmechanic Jul 30 '16 at 5:30
• I still can not see the difference between DYNAMICS and KINETICS? – Sulaiman Alessa Jul 30 '16 at 5:35
• Welcome to Physics Stack Exchange. Please do not use words in all capital letters. It is completely unnecessary and makes the text harder to read. Also please note that any time you write a question with a numbered list, that is almost certainly indicating that the post should be broken into several more focused posts. – DanielSank Jul 30 '16 at 6:20

$$\sum \vec F=0 \qquad \sum\vec\tau=0$$
• Dynamics and kinetics: The study of the causes of (changes in) motion. That would be forces and torques etc. Newton's 2nd law tells the connection: $$\sum \vec F=m\vec a\qquad \sum \vec \tau=m\vec \alpha$$ The word dynamics took over more and more over the past 100 years, but as far as I'm aware the two words are used interchangeably depending on the field of science.