A police radar gun operates at a frequency of 10.5 GHz.The offi cer, sitting in a patrol car at rest by the highway,directs the radar beam toward a speeding car traveling80 mph directly away from the patrol car. What is thefrequency shift of the refl ected beam, relative to theoriginal radar beam?
Chapter 17 Notes Sec. 1: Newton’s First Law: If no force acts on a body, then the body’s velocity cannot change Newton’s Second Law: F = ma Newton’s laws of motion allow us to analyze many kinds of motion Conservation of energy Ki +Ui = Kf +U f In an isolated system where only conservative forces cause energy changes, the kinetic energy and potential energy can change, but their sum cannot change Gravitational and electro-magnetic forces: this what we experience!!! Frictional force, spring force, normal force, tension force in a string, aerodynamic force … are results of electromagnetic force Sec. 2 An electric charge has a magnitude and sign. It is either positive or negative. Electron has negative electric charge. Proton has positive electric charge Sizes and masses Atoms are combinations of equal amounts of electrons and protons. The neutrons provide the glue to stick together the protons in the nucleus. The proton and the neutron are about 2000 times heavier than the electron, so the vast majority of an atom’s mass resides in the nucleus. Atoms are mostly … empty. We live in almost empty space *Example: tennis ball and a grain of sand Materials – two extreme models Insulators – a material in which charges do not move freely though the interior of the sample. Examples: Glass, wood, rubber, plastics, stone, brick, etc Conductors – material where free charges can move through the material. Examples: Ionized gases (plasmas), metals, ionic solutions if salts in water Semi-c