9/ 26/13 Intro to Velocity

1. 9/26/13Intro to Velocity • Start a new page in your notebook. Title is as above. Add this to your table of contents. • Science podcast: Wind Round-up • Brief science notebook overview • Discuss motion, displacement and the “v” word • Constant motion car • Brief graphing overview • Running outside • One minute reflection • Homework: Worksheet Describing motion verbally with speed and velocity, associated reading

2. Learning objectives for the day • Using everyday language, describe how to determine whether an object has uniform motion • Use words or a formula to define velocity

3. Your PHYS 106 notebook PHYS 106 Notebook Your Name Fall 2013 Instructor: Bruce Palmquist • The first page is the table of contents. Number it i. • The second page is also the table of contents. Number it ii. • Right hand pages are for entries. • Left hand pages are for attaching worksheets. • All writing MUST be in pen. Do not erase. If you made a mistake, put a single line through if it. • Initial and date each page near the page number when you finish.

4. PHYS 106 Notebook • All notes, activities, brainstorming should be done on the right-hand pages of your quadrille PHYS 106 notebook. • The format is as follows. Always use the date and title of the first class slide in your table of contents and on the first note page of that day. Table of Contents Activity title (Date)……………………..…….Page Blindfold Navigation (9/25/13)…………...1 Intro to Velocity (9/26/13)……………….(2)

5. Constant motion • We can define motion by the ratio: Motion ratio = displacement/change in time • Displacement is how far out of place an object is compared to when it started; it is the object's overall change in position. This has a direction. • Review homework • Given the tools in the front of the classroom, determine the motion ratio of your car. • Is the ratio constant? How do you know. Devise a method to test if the ratio is constant. Write a one sentence description of what you did to provide evidence that the ratio is or is not constant. • Each group will text 754845 and your sentence to 22333

6. Observations?

7. The “V” word • You probably realized that you were looking for constant velocity. • For easily measurable time intervals • v = ∆x/∆t where x is position (∆x is displacement or “change in” position) and t is clock reading (∆t is duration or “change in” time) • ∆ means “change in” OR • final value – initial value • Sample problems based on HW, previous activity, and instructor’s motions

8. Graphing motion • A graph is simply another way to organize data • To make a position vs time graph, plot time along the x-axis and position along the y axis. • Sketch a best-fit line through or near each point. Don’t just connect the dots.

9. Running outside (if time) • Set up two 30 meter courses outside. Have people with a stopwatch at 5 meter intervals. • Select three runners. • Get a head start to reach a speed, keep that constant speed from the official start line to the 30 meter mark. • Get a head start to run fast, slow down continually from the start line to the 30 meter mark. • Start from rest at start line, speed up continually to the 30 meter mark. • Timers start their watch when runner is at start line. They stop their watch when the runner passes them. • Make a position vs time graph for each runner • (Calculate the velocity column) if time permits

10. One minute reflection • About once a week, you will take a minute to write a brief reflection of what you learned in the past week. Let these questions guide you. • What new content did you learn? • What new skills did you learn • How can you use what you learned in the future? • What questions do you still have? • You need not answer all of these questions. Use them if you are having trouble thinking of something to write.