Physics (Overview)

Physics is the scientific study of matter, its fundamental constituents, its motion and behavior through space and time, and the related entities of energy and force.  Physic theories can be classified into  two main categories:

• Conventional physics:  An object is defined by its position and velocity, the evolution of which can be predicted. 

• Quantum physics: An object with mass is described by its wave function. Its probabilities of being present at a given location and time can be defined.

Conventional Physics (Macroscopic)

Newton Laws (Solid) (1687)

Newton's laws of motion are three physical laws that describe the relationship between the motion of an object and the forces acting on it. These laws provide the basis for Newtonian mechanics and can be stated as follows:

• An  object that are not influences by forces remains at rest, or moves at a constant speed in a straight line, unless it is acted upon by a force.

• At any instant of time, the net force on a body is equal to the body's acceleration multiplied by its mass or, equivalently, the rate at which the body's momentum is changing with time.

• If two bodies exert forces on each other, these forces have the same magnitude but opposite directions.

Navier-Stokes Laws (Liquid, Gas)

The Navier–Stokes equations are partial differential equations which describe the motion of viscous Newtonian fluid substances such as gas and liquids (Viscosity).

Einstein Laws (1905) (Particle, Planet)

These laws provide the basis for theory of special and general relativities and can be stated as follows:

• An  object that are not influences by forces moves along geodesic curves in space time, unless it is acted upon by a force.

• The laws of physics are the same and can be stated in their simplest form in all inertial frames of reference. 

• The speed of light c is a constant, independent of the relative motion of the source. 

Quantum Physics (Microscopic Laws)

Quantum mechanics is the fundamental physical theory that describes the behavior of matter and of light. Its haracteristics typically occur at and below the scale of atoms.  (More information)