Lec02_Sum_f

# Lec02_Sum_f - Summary Lecture 2 In physics we use the...

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Lecture 2 Types of Motion Acceleration Vertical Motion Physics 111, Summer 2011, June 14, Lecture 2 Summary Velocity has both the magnitude and direction (a vector). In physics we use the System International (SI) or the metric system. 2 Instantaneous velocity is the change in position divided by very short time (t zero): Speed has only the magnitude (a scalar). 0 / Δ Δ Δ = t when t x v inst For motion we need to know distance , time , speed , velocity , and acceleration . An average velocity is the change in position (displacement) divided by the change in time: An average speed is the distance traveled divided by the total time: Mechanics : (1) Kinematics explains how objects move . (2) Dynamics : explains how objects motion depends on forces acting on them. t d v t d v total total / / = = t x v Δ Δ = / Physics 111, Summer 2011, June 14, Lecture 2 3 Types of Motion - motion along straight line. Vertical motion Horizontal motion - motion along a circular path (horizontal or vertical). - motion up, down, free fall. Circular motion Two dimensional and projectile motion - motion along both horizontal and vertical directions. y x For most of types of motion we can use one or two axis: y y x x Physics 111, Summer 2011, June 14, Lecture 2 Acceleration (#1) 4 “a” is a symbol for acceleration An object changes its velocity if: - it moves faster, or - it moves slower. - motion along straight line. Horizontal motion Acceleration tells us: 1. How quickly the velocity changes. 2. How quickly the position changes. y

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## This note was uploaded on 02/11/2012 for the course PHYSICS 111 taught by Professor B during the Summer '08 term at Iowa State.

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Lec02_Sum_f - Summary Lecture 2 In physics we use the...

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