Einstein's 1905 Annus Mirabilis papers laid foundation for modern physics. Explained Brownian motion, confirming existence of atoms and molecules. Determined Avogadro's number through statistical atomic behavior analysis
Motion occurs when an object changes position relative to a reference point. Kinematics describes motion without considering forces, dynamics studies forces. Everything in the universe is in constant motion. Motion applies to objects, matter, radiation, and space-time
Scalars are physical quantities described by single pure numbers with units. Examples include length, mass, charge, volume, time, speed, and pressure. Scalars represent magnitude of quantities, like speed is to velocity
There are four fundamental forces: gravity, electromagnetism, weak, and strong. These forces are not reducible to more basic interactions. Matter consists of fermions that exchange virtual particles called gauge bosons
A frame of reference is an abstract coordinate system with specified origin and scale. Reference points are identified mathematically and physically. In n dimensions, n+1 reference points are sufficient to define a frame
Acceleration is the rate of change of velocity with respect to time. Acceleration is a vector quantity with magnitude and direction. SI unit is metre per second squared (m⋅s−2)