This document summarizes key concepts in Newtonian mechanics. It defines important terms like position, displacement, velocity and acceleration. It describes one-dimensional and multidimensional motion. It introduces Newton's three laws of motion: 1) an object at rest stays at rest and an object in motion stays in motion unless acted upon by an external force, 2) the relationship between force, mass and acceleration, and 3) for every action there is an equal and opposite reaction. Equations of motion are provided. Examples of applications of Newton's laws are given for planetary motion and other topics. The importance of properly understanding and applying formulas is also discussed.