Follow the idea
Newton’s laws connect forces to changes in motion. In an inertial frame, the net force determines acceleration through the relation F = ma. The laws are powerful because they turn a force diagram into predictions about motion; the difficult part is often identifying the system and forces correctly. Energy can move between stores and cross a system boundary, but for an isolated system total energy is conserved. Thinking in terms of energy often lets us solve a problem without following every detail of the motion. Masses attract one another. Newton’s law gives an inverse-square force, while the gravitational-field viewpoint describes how a mass changes the space around it for other masses. The same framework connects falling objects, planetary motion and satellites.
Primary references
IUPAC Gold Book · NIST · BIPM