Review of Classical Physics Uniersity of Central Florida中佛罗里达大学的古典物理学评论.pptVIP

Review of Classical Physics By the late part of the 19th century, physics consisted of two great pillars: a) mechanics including thermodynamics and b) electromagnetism. However, a series of problems that should have been solvable continued to perplex physicists. Modern physics is the study of the two great revolutions (relativity and quantum mechanics) that solved these problems and our continuing effort to find the ultimate rules of the game. Classical Physics General Ideas of Mechanics 1. A reference frame is a coordinate axis and origin used by an observer to describe the motion of an object. 2. An inertial reference frame is one in which the observer is not accelerating (i.e. one in which Newtons Laws are valid without adding fake forces to your free-body diagram) Question: Accelerating with respect to what? Galilean Relativity All inertial reference frames are equivalent! Another way of stating this principle is that only relative motion can be detected. Transformation Equations If you know what an observer in a particular reference frame observes then you can predict the observations made by an observer in any other reference frame. The equations that enable you to make these calculations are called Transformation Equations. Invariance Since the labeling of your coordinate axis and its origin location is arbitrary, the equations of physics should have the same form regardless when you rotate or translate your axis set. Equations that have this property are said to be invariant to the transformation. It was shown that Maxwells Equations are not invariant under a Galilean Transformation so EM and Mechanics are not consistent. General Ideas of EM 1. Light is a transverse wave. 2. The speed of light depends only on the medium through which it travels and not upon the observer. 3. The light propagates from the sun to the earth through the luminiferous ether. 4. Properties of the Ether Fluid i) non-viscous - Earth does