The word "mechanics" and the field itself came about by engineers generally by studying how machines work, to improve existing designs and build more advanced machinery.
Kinematics specifically relates to the motion in isolation from the various forces that cause these motions.
This is compared to "dynamics", which deals with both motion of objects and as well as the various forces that cause them. This is where we get into Newton's three laws of motion.
- The Law of Inertia: Objects resist change. Things that are in rest will remain in rest. Things in motion will remain in motion. Until a force acts upon them. This is called inertia.
- The Law of Acceleration: Objects accelerate in proportion to the net force applied to them. They decelerate the more mass they have. f = ma describes this relationship.
- The Law of Action and Reaction: When an object applies a force on another object, the other object applies an equal force in reaction.