Physics 1110 Fall 2004L1 - 1Lecture 1 23 August 2004In today’s lecture, Prof. Dessau and I introduced ourselves to theclass and then went over the syllabus for the course. A copy of thesyllabus as well as all relevant information about the course can befound at the course home page athttp://www.colorado.edu/physics/phys1110/These lecture summaries will in general not be quite so chatty asbelow. Since we will spend a lot of time in lecture doing concept testsand checking understanding, they will typically emphasize only themajor points. They are not a substitute for reading the text!Mechanics and Motion DiagramsPhysics is the study of how the universe works! It is not a collection offormulas but rather a method of analyzing Nature, which has yieldedenormous insight. At the beginning of our study of physics, we beginwith the most fundamental topic, mechanics, which is the study ofmotion. Clearly without motion we wouldn’t be here to study this, butthere also wouldn’t be anything much to study. No matter whetheryou are investigating the creation of stars, the quarks in the nucleon,the replication of DNA or the stability of a building during anearthquake, you are fundamentally concerned with the motion of theconstituents of whatever you are studying. Thus, our study of physicshas to begin with mechanics.While you it may not be apparent and you may not even believe it, allobjects that humans have ever investigated follow the same laws ofmotion. This is not to say that all objects have the same motion(though this is often the case!). Rather, it means that when weanalyze the motion of objects, we do not have to have a separate setof rules for different types of objects. One of the central themes ofphysics is the search for the universal principles governing nature.We all experience motion, and therefore each of us has a wealth ofintuition and terminology to describe motion in our everyday speech.Physics 1110 Fall 2004L1 - 2Unfortunately, a lot of our intuition is warped by the fact that motion inour everyday experience is strongly influenced by gravity and friction.Another difficulty in studying mechanics is that many of the Englishwords we use to describe motion are used in a vague way (oftenbecause our thinking about the details of motion is vague) and in ourstudy of mechanics, we will give many of these words specific andprecise meanings. Thus there is always the danger of slipping backinto vague ideas because of the use of these words. So be on guard!It may help to keep a list of the special “double” use words (such asacceleration, speed, and velocity) and when you start to use them inphysics class, remind yourself of their physics definition. Eventuallyyou’ll get used to their split personality, and you won’t have toconsciously remind yourself about them.Given this uncertainty in words, we will first develop a pictoriallanguage to describe motion in a way that is fundamental to ourunderstanding of movement and will give us a way to ground ourphysics discussion in a common understanding of the actual motion.The motion diagram is the essential subject of Chapter 1 in Knight,which you should read before Wednesday’s lecture. While thislanguage is qualitative (i.e., you can’t use it to calculate anythingprecisely), it is nonetheless a critical component of the conceptualunderstanding of mechanics. Someone who could solve theequations for a particular motion, but who could not draw thecorresponding motion diagram would not be said to have understoodthe physics of the
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