Lesson 1: Describing Motion with Words Introduction to the Language of Kinematics Scalars and Vectors Distance and Displacement Speed and Velocity Acceleration Lesson 2: Describing Motion with Diagrams Introduction to Diagrams Ticker Tape Diagrams Vector Diagrams Lesson 3: Describing Motion with Position vs. Time Graphs The Meaning of Shape for a p-t Graph The Meaning of Slope for a p-t Graph Determining the Slope on a p-t Graph   Lesson 4: Describing Motion with Velocity vs. Time Graphs The Meaning of Shape for a v-t Graph The Meaning of Slope for a v-t Graph Relating the Shape to the Motion Determining the Slope on a v-t Graph Determining the Area on a v-t Graph   Lesson 5: Free Fall and the Acceleration of Gravity Introduction to Free Fall The Acceleration of Gravity Representing Free Fall by Graphs How Fast? and How Far? The Big Misconception   Lesson 6: Kinematic Equations The Kinematic Equations Problem-Solving Kinematic Equations and Free Fall Sample Problems and Solutions Kinematic Equations and Graphs     Lesson 2 : Describing Motion with Diagrams Ticker Tape Diagrams A common way of analyzing the motion of objects in physics labs is to perform a ticker tape analysis. A long tape is attached to a moving object and threaded through a device that places a tick upon the tape at regular intervals of time - say every 0.1 second. As the object moves, it drags the tape through the "ticker," thus leaving a trail of dots. The trail of dots provides a history of the object's motion and therefore a representation of the object's motion. The distance between dots on a ticker tape represents the object's position change during that time interval. A large distance between dots indicates that the object was moving fast during that time interval. A small distance between dots means the object was moving slow during that time interval. Ticker tapes for a fast- and slow-moving object are depicted below. The analysis of a ticker tape diagram will also reveal if the object is moving with a constant velocity or accelerating. A changing distance between dots indicates a changing velocity and thus an acceleration. A constant distance between dots represents a constant velocity and therefore no acceleration. Ticker tapes for objects moving with a constant velocity and an accelerated motion are shown below. And so ticker tape diagrams provide one more means of representing various features of the motion of objects.   Check Your Understanding Ticker tape diagrams are sometimes referred to as oil drop diagrams. Imagine a car with a leaky engine that drips oil at a regular rate. As the car travels through town, it would leave a trace of oil on the street. That trace would reveal information about the motion of the car. Renatta Oyle owns such a car and it leaves a signature of Renatta's motion wherever she goes. Analyze the three traces of Renatta's ventures as shown below. Assume Renatta is traveling from left to right. Describe Renatta's motion characteristics during each section of the diagram. Use the pop-up menu to check your answers. 1. Depress mouse to view answers. Renatta decelerates from a high speed to a low speed until she is finally stopped. She remains at rest for a while and then gradually accelerates until the trace ends.     2. Depress mouse to view answers. Renatta travels at a constant speed during the first time interval and then gradually accelerates until the trace ends.       3. Depress mouse to view answers. Renatta moves with a constant speed in the first time interval. She then abruptly decelerates to a stop. She remains at rest for sometime and then moves with a constant speed, slower than the first speed.

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© Tom Henderson, 1996-2001