PHY093 Physics 1 Introduction
Physics (Giancoli) • The most basic of the sciences • Deals with behavior and structure of matter • Usually divided into • (a) classical physics: motion, fluids, heat, sound, light, electricity and magnetism • (b) modern physics: relativity, atomic structure, condensed matter, nuclear physics, elementary particles and astrophysics
Why study physics? (Giambatista et al.) • Since physics describes matter and its basic interactions, all natural sciences are build on a foundation of the laws of physics. • In today’s technological world, many important devices can be understood correctly with the knowledge of the underlying physics.
Fiber optics carry signals efficiently based on the principle of total internal reflection
Why study physics? • By studying physics, you acquire skills that are useful in other disciplines. • Society’s resources are limited, so it is important to use them in beneficial ways and not squander them on scientifically impossible projects. • By studying physics, we hope that you develop a sense of beauty of the fundamental laws governing the universe.
The nature of physics(Cutnell & Johnson) • The science of physics has developed out of the efforts of men and women to explain our physical environment. • The exciting feature of physics is its capacity for predicting how nature will behave in one situation on the basis of experimental data obtained in another situation. Such predictions place physics at the heart of modern technology.
Length or distances studied in physics (order of magnitude) • Radius of proton or neutron 10-15 m • Atom 10-10 m • Virus 10-7 m • Height of Mount Everest 104 m • Earth diameter 107 m • Sun diameter 109 m • Distance earth to sun 1011 m • Farthest galaxy visible 1026 m
Some masses (approx.) • Electron 10-31 kg • Proton / neutron 10-27 kg • DNA molecule 10-17 kg • Mosquito 10-5 kg • Person 102 kg • Ship 108 kg • Earth 6 x 1024 kg • Sun 2 x 1030 kg • Galaxy 1041 kg