1. Bell Ringer 25 June 2009

2. LT: Interpret a distance-time graph to properly describe the motion of an object. Discuss with your team how the motion of an object can be described with a graph.

3. Describe tumble buggy motion Define the system - What must we include; what may we disregard? Define the variables - What aspects are likely to change in our description of the motion?

4. Making a distance-time graph Start your stopwatch when car passes the starting line. Every 5 seconds place a washer beside the tumble buggy’s position (distance measured from the starting line). Record distance and time, and make a d-t graph.

5. Interpreting a dist-time graph

6. Best-fit Line for Tumble Buggy Determine expected model of best-fit line (e.g., proportional, linear, inverse). Determine if line must pass through origin. Fit line so that it minimizes the sum of all vertical deviations (residuals) from that line. Correct Fit Minimize Residuals

7. Interpreting Slopes To find slope, identify two points on best-fit line. Identify one point’s coordinates as (x P, y P ) and the other point’s coordi- nates as (x R, y R ). Calculate slope = change in y divided by change in x. Slopes can be + (a and b), - (c and d), 0 (horizontal), or infinite (vertical).