# Second Law of Dynamics

Hi everyone! I saw in an old exam of physics : "Write and comment the second law of dynamics."

And i was thinking, I know a lot about it and if i had to answer it i would have made some examples, but when he asks me to comment it ? What should i have to say ?
In sense, what do you think are the really important things/conseguences about the second law of dymics that need to be mentioned ?

## Answers and Replies

By "second law of dynamics" do you mean Newton's Second Law?

If that's the case, I would say that Newton's profound insight was that there exists some physical quantity, which we now call "force," whose effect is NOT to keep bodies in motion, but rather whose effect is to modify otherwise uniform motion. In other words, a force need not be applied to keep a body in motion, but rather it be applied to change the state of motion.

Truly profound.

They're probably talking about the Second Law of Thermodynamics.

Thank you very much! Yes i was talking about the second law of Newton!
Yes i understand now!