Constant velocity presentation

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  • 1. Kinematics Study of How Things Move
  • 2. What am I doing? How do you know?
  • 3. Frame of Reference All motion is relative. What does that mean?
  • 4. Car Commercial
  • 5. Describing Motion
  • 6. What can we measure? Science is about Quantitative Descriptions
  • 7. What relationship are we trying to determine? From the useful measurements, what is our objective? To find a relationship between what and what?
  • 8. What should we do with the data? So we are making measurements, but what do we do with them? • Table? What do we put in the table? So we need signs for those things, right? o t=time and x=position (y if vertical) • When our table is full of data, then what? o Graph it! We need axes. Which variable goes on which axis? o Time is independent (x-axis) o Position depends on the time (y-axis) • Alright! Let’s do this! Wait, what are we doing?
  • 9. The Breadcrumb Method How we collect data Do NOT write down this data. It’s not yours! • Mark Origin • Mark Starting Point (different from origin, positive or negative) • Sync the stopwatch and the starting of the buggy (figure it out) • Use tape tick marks to mark the position of the back of the buggy every 2 seconds.
  • 10. Jobs • Meter Stick – grab a meter stick for the group • Stopwatch – grab a stopwatch for the group • Taper – grab a role of tape for the group • Data Collector – take data in a table for the group
  • 11. Whiteboards With your group, sketch your graph on a whiteboard. Don’t use a meter stick or make tick marks, make a general sketch. Write the equation of line of best fit near your sketch. When you’re finished, gather around for a … wait for it… board meeting! Get it?
  • 12. Board Meeting Class discussion. Sit so everyone can see the boards. I’ll help lead the discussion this time, but eventually you won’t need me as much. What’s the same about everyone’s boards? What’s different?
  • 13. The Take Home Slope of the position-vs-time graph is Velocity. Positive or Negative tells us direction. Steepness tells us magnitude.
  • 14. Constant Velocity Particle Model Look at all the pieces of our model: • Verbal piece from our observations • “Breadcrumb” motion map on the floor/table • Table of data points • Position-vs-time graph features What’s left in the CVPM? • Velocity-vs-time graphs
  • 15. The Test!
  • 16. Homework “Motion Maps” Reading It’s 1 page, front and back. There’s a lot of pictures. Deal with it! Put ?’s next to words you don’t know. Make notes in the margin. Come ready to talk about motion maps!
  • 17. Day 2 – Constant Velocity Sched: • Starter • Recap • Wkst 1 Starter: If you’re driving on the highway at 70mp… A. How far down the road will you be in 3.5 hours? B. How long will it take you to go on a 300 mile trip?
  • 18. And the answers are… • Starter: If you’re driving on the highway at 70mp… • A. How far down the road will you be in 3.5 hours? o 245 miles • B. How long will it take you to go on a 300 mile trip? o About 4.3 hours Objective: TLWBT read graphs, table, motion maps and written descriptions and express motion in graphs, table, motion maps and written descriptions
  • 19. Let’s Recap Frame of Reference • In order to describe motion, you have to pick a “frame of reference” o Frame of reference is always decided by the observer o In physics we often use a coordinate axis to denote our frame of reference.
  • 20. Frame of Reference -x -Y x Y This is a familiar coordinate axis, but in physics it has a slightly different meaning.
  • 21. Frame of Reference • In this frame of reference, up is positive, right is positive • Down in negative, as is left • Hence in physics a negative has no value, it merely denotes direction • This is necessary because direction has a special distinction in physics; it separates vector quantities from scalar quantities
  • 22. Vector vs. Scalar • A Scalar Quantity is one that has only magnitude – distance is a scalar o Example: If you travel 500 miles that is a distance • A Vector Quantity is one that has magnitude and direction – displacement is a vector o Example: If you travel 500 miles North this is displacement
  • 23. Distance and Displacement • Distance is a scalar. Think about a pedometer or an odometer. o Example: If you travel 500 miles that is a distance • Displacement is a vector. Displacement is the shortest path from start to finish. “As the crow flies.” o Example: If you travel 500 miles North this is displacement
  • 24. Distance and Displacement Let’s say you walk 5m to the right, 3 meters up, another 5 meters to the right, and finally 4 meters up. Your distance is the total meters you walked: 17m. Your displacement is simply the difference between finish and start: ~12m. 5m 5m 3m 4m ~12m
  • 25. Speed and Velocity If you divide distance by time you get average speed (scalar) • Example: S = D/t = 500 miles/2 hours =250 mph If you divide displacement by time you get average velocity (vector) • Example: Vavg = Δx/Δt = 500 miles North/2 hours = 250 mph North
  • 26. Motion Maps
  • 27. Cooperative Learning
  • 28. Whiteboard Worksheet 1 I will present a problem from the worksheet. In groups, you will talk through and solve the problem on the whiteboard. Really work through it and make sure each group member really understands. We will talk about answers and misconceptions. Then, as a class we can write correct answers and ideas on our worksheets.
  • 29. Day 3 – Constant Velocity Sched: • Starter • Check Wkst1 • V vs T graphs • Wkst2 TLWBAT interpret and draw V vs. T Graphs. Starter: How far does your car travel when you one- handedly text “LOL” to your friends.
  • 30. Velocity vs. Time Graphs Let’s make some guesses!
  • 31. Whiteboard Worksheet2 In groups, you will talk through and solve the problem on the whiteboard. Really work through it and make sure each group member really understands. We will talk about answers and misconceptions. Then, as a class we can write correct answers and ideas on our worksheets.
  • 32. Units of Area on V vs. T Graphs
  • 33. Day 4 – Constant Velocity Sched: • Starter • Motion Detector Lab • Quiz? TLWBAT reenact physically any motion given in a prompt. Starter: Find the total distance covered and total displacement.
  • 34. Buggy Lab Part 2 Battle Royale 2m Where will they hit each other?