Force
Sir Isaac Newton described the motion of all objects using the concepts of inertia and force, and in doing so he found they obey certain conservation laws. In 1687, Newton published his thesis "Philosophiæ Naturalis Principia Mathematica". In this work Newton set out three laws of motion that to this day are the way forces are described in physics.
Physicist
The study and practice of physics is based on an intellectual ladder of discoveries and insights from ancient times to the present. Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture, for example in the work of Euclid, Thales of Miletus, Archimedes and Aristarchus. Roots also emerged in ancient Asian culture and in the Islamic medieval period, for example the work of Alhazen in the 11th century. The modern scientific worldview and the bulk of physics education can be said to flow from the scientific revolution in Europe, starting with the work of Galileo Galilei and Johannes Kepler in the early 1600s. Newton's laws of motion and Newton's law of universal gravitation were formulated in the 17th century. The experimental discoveries of Faraday and the theory of Maxwell's equations of electromagnetism were developmental high points during the 19th century. Many physicists contributed to the development of quantum mechanics in the early-to-mid 20th century. New knowledge in the early 21st century includes a large increase in understanding physical cosmology.