This article is about an area of scientific study. It can also be defined as a branch of science which deals with the motion of laws of mechanics pdf forces on objects. Quantum Mechanics was discovered in the early 20th century.
Both are commonly held to constitute the most certain knowledge that exists about physical nature. The correspondence principle states that the behavior of systems described by quantum theories reproduces classical physics in the limit of large quantum numbers. Quantum mechanics has superseded classical mechanics at the foundation level and is indispensable for the explanation and prediction of processes at the molecular, atomic, and sub-atomic level. However, for macroscopic processes classical mechanics is able to solve problems which are unmanageably difficult in quantum mechanics and hence remains useful and well used. Until about 400 years ago, however, motion was explained from a very different point of view. He showed that the speed of falling objects increases steadily during the time of their fall.