2010 Pearson Education, Inc. Week 4 Day 2: Topics Slide 1-7 Particle Model Motion Diagrams Adding and Subtracting Vectors Graphically Delta v diagrams 2010 Pearson Education, Inc. A graph of velocity versus time for a hockey puck shot into a goal appears like so: Which of the following position graphs matches the above velocity graph? Checking Understanding A.B.C.D. Slide 2-21 2010 Pearson Education, Inc. A graph of velocity versus time for a hockey puck shot into a goal appears like so: Which of the following position graphs matches the above velocity graph? Answer A.B.C.D. Slide 2-22 2010 Pearson Education, Inc. Example Problem A car moves along a straight stretch of road. The graph below shows the cars position as a function of time. At what point (or points) do the following conditions apply? The displacement is zero. The speed is zero. The speed is increasing. The speed is decreasing. Slide 2-14 2010 Pearson Education, Inc. Examples of Motion Diagrams 5 2010 Pearson Education, Inc. The Particle Model A simplifying model in which we treat the object as if all its mass were concentrated at a single point. This model helps us concentrate on the overall motion of the object. Slide 1-16 2010 Pearson Education, Inc. Position and Time The position of an object is located along a coordinate system. At each time t, the object is at some particular position. We are free to choose the origin of time (i.e., when t = 0). Slide 1-17 2010 Pearson Education, Inc. Slide 1-7 Which Way? Which way is this object moving? A.LeftB. RightC. Cant tell Is it speeding up or slowing down? A.Speeding upB. Slowing down C. Cant tell How can you tell? 2010 Pearson Education, Inc. Here is a motion diagram of a car moving along a straight stretch of road: Which of the following velocity-versus-time graphs matches this motion diagram? Checking Understanding A. Slide 2-13 B.C.D. 2010 Pearson Education, Inc. Here is a motion diagram of a car moving along a straight stretch of road: Which of the following velocity-versus-time graphs matches this motion diagram? Slide 2-14 C. Answer 2010 Pearson Education, Inc. Vectors Slide 3-9 2010 Pearson Education, Inc. Adding Vectors Graphically Slide 1-33 2010 Pearson Education, Inc. Adding Displacement Vectors Slide 1-31 2010 Pearson Education, Inc. Example: Adding Displacement Vectors Jenny runs 1 mi to the northeast, then 1 mi south. Graphically find her net displacement. Slide 1-32 2010 Pearson Education, Inc. Slide 1-7 Adding Vectors Find the following resultants graphically 2010 Pearson Education, Inc. Vector Subtraction Slide 3-10 2010 Pearson Education, Inc. Slide 3-11 Acceleration Vectors