9/25/13, Wednesday

Post date: Sep 25, 2013 12:38:6 PM

Bell Ringer

    • An object falls from rest under the influence of gravity and air resistance. Sketch graphs of position vs. time, velocity vs. time, and acceleration vs. time for the object. For each graph, explain why you drew it the way you did.

Activities

    • Bell ringer

    • Work on air resistance labs

      • Data analysis / graphing

        • Need data tables of time and position for one trial of each variation of your experiment

        • Make separate graphs for each data set

        • Use each graph to determine the terminal velocity of the object or the time it took to reach the terminal velocity

        • Make a new table that includes your independent variable (mass, surface area, etc.) and the terminal velocity or time to reach terminal velocity for each

        • Make a new graph of that data to draw conclusions from

      • Questions for analysis (goes with the "what did you learn" part)

        • How much force did air resistance provide at the moment you dropped each object?

        • What was the maximum force from air resistance for each variation? (could be numbers, could be expressed in terms of other quantities)

        • Draw free body diagrams for an object falling that has a) just been released, b) been falling only for a few moments (not yet reached terminal velocity), and c) been falling long enough to reach terminal velocity. Based on these diagrams, is acceleration constant in these problems? Would it be valid to use the kinematics equations to solve problems like this? Why or why not?

        • Include a statement of what you learned regarding your group's purpose

Assignment

    • Pages 145 - 149: 9, 10, 19, 20, 22, 31, 35, 38, 48, 50 due Friday, 9/27

Announcements

    • Chapter 4 test Monday, 9/30