It is often instructive to examine how scientific ideas develop over time. If you are interested, explore how Newton formulated the laws of motion by reading excerpts from his original work, the Principia. Both the original text and commentaries are available online.
The development of the laws of motion shows how scientific ideas evolve over time. In ancient times, it was mistakenly thought that a force was required to keep an object moving with a constant velocity.
This changed in the 17th century when Galileo Galilei used thought experiments to argue that if a body moves along a horizontal plane and all impediments to its motion are removed, it will continue to move indefinitely.
Building on this, Isaac Newton used the word inertia to describe the tendency of objects to resist change in their state of rest or uniform motion. He used this idea to frame his first law of motion: an object remains at rest or in constant velocity unless a net force acts on it.
In 1687, Newton presented his three laws of motion. The second law states that acceleration is proportional to net force and inversely proportional to mass. The third law states that interacting objects exert equal and opposite forces on each other simultaneously.
The formulation of these laws was a defining moment in history. They describe motion across enormous scales, needing modification only at atomic scales, near the speed of light, or near massive objects.
Explanation
The question asks students to explore how Newton formulated his laws of motion over time. The provided context traces this historical development from the ancient misconception that a force is needed to maintain motion, to Galileo's thought experiments introducing inertia, and finally to Newton's synthesis of these ideas into his three laws of motion in 1687. The answer highlights this progression using only the facts provided in the text.