Newton's Laws, Part 1

Isaac Newton invented physics, or at least got it off the ground. Possibly one of the most brilliant scientists of his generation, Newton tackled the laws of motion and gravity with an insight that was ahead of his time. There are two important sets of laws that Newton came up with. One is the laws of motion, often called mechanics, and the law of gravity.

We'll start with his laws of motion, of which there are three.

The First Law is the one that says that if something with mass is in motion or at rest it will remain at motion or at rest unless an outside force acts upon it.

Math wise it would be ∑ F = 0 ≈ dv/dt = 0  which says that if a change in force is zero it's equivalent to a change in velocity (acceleration) being zero.

This law depends upon a state of reference, which would be inertia. Inertia is that property of matter that resists change, either positive or negative.

The Second Law quantifies the force needed to accelerate or decelerate an object with mass.
Math wise it's F=ma or Force is equal to mass times acceleration, in which a = dv/dt or the change in velocity with time. This concept indicates that mass has momentum and that it takes force to change its momentum.

The Third Law is the familiar concept that applying a force to one object causes an equal reactive force from the second force-applying object. This is also known as the action-reaction law. This law is how rockets work. By blasting expanding hot gas out of rocket's nozzle one can make the rocket shoot up into the sky.

Math wise it's Fa = - Fb or Force a is reacted upon in the opposite direction by Force b.
It's surprising how obvious these law appear to us in this modern age, but back in the 17th and early 18th century people did not understand how mechanical things worked other than by experience. Isaac Newton quantified these amazing concepts and began what is now considered modern physics. He deserves all of the accolades that has been given to him.

Thanks for reading.