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Unformatted text preview: Chapter 3 Study Guide for Velocity 3.1 From reality to model Skill 3.1 Understand conceptually how real systems are modelled using tables, graphs and equations Kinematics is the quantitative study of motion. In order to study the motion of an object at the most basic level, a model of the system in question must be created. This model is a simplified, abstract representation of the real world system. We use all the time in physics to obtain a basic understanding of how things work and to make predictions about how things will behave in future experiments. These models can be represented by graphs, tables, or equations, and the models used by scientists can vary in complexity a great deal. For the purposes of this course (for the time being, anyway), objects will only be particles: cars, people, balls, etc. will all be treated as point-like objects. This makes locating the position of the object, an important piece of physical information describing the location of the object in relation to some reference point, a lot easier because the physical dimensions of the object can be ignored. Also the causes and restraints of the motion, like whats pushing or pulling on the object (a bat on a ball, air resistance on a car, for example) will be ignored. So, for the next few weeks, we wont be deadly accurate in our calculations of the velocity of a projectile because our model wont take every factor into account, but well be close enough to gain a basic understanding of how to quantify the motion of an object. 3.2 Calibrating the data Skill 3.2 Understand the importance of calibrating data Communicating data is of the utmost importance in the scientific community. Standards of measurement have been established so that scientists can effectively calibrate their experimental data. Most of these standards are common sense to us today, like using seconds to measure time or a ruler or meterstick to measure the length of an object (as opposed to comparing the length of a pencil to the length of a book). 3.3 Position and displacement Skill 3.3 Understand the difference between position, displacement, and distance trav- elled Another necessity when describing the location and motion of an object is to be precise in the language used. The following terms are important and mandatory when describing the location and movement of an object. 1 Definition of Position: An objects position is its location relative to the origin in some coordinate system. Position therefore depends on the choice of origin and on the orientation of the coordinate system being used. Definition of Displacement: An objects displacement is the change in its position (usually over some time interval). Displacement is independent of the choice of origin....
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This note was uploaded on 05/04/2008 for the course PHYS 2054 taught by Professor Stewart during the Spring '08 term at Arkansas.
- Spring '08