Final answer:
Newton relied on his observations, experiments, and mathematical principles of calculus when describing the laws of the universe in his publication Principia
Step-by-step explanation:
When Newton described the laws of the universe in his 1687 publication Principia, he relied on his observations and experiments, as well as the mathematical principles of calculus. One of the key concepts Newton used was the law of motion, which stated that an object at rest tends to stay at rest, and an object in motion tends to stay in motion with the same speed and in the same direction, unless acted upon by an external force. He also introduced the concept of gravitational force, which explained how objects are attracted to each other based on their mass and distance.
Learn more about Newton's laws of motion and gravitational force