Class on 9/9/09

First, we took reassessment number 3. Then we went over the homework, which was the Photo Finish Followup. We analyzed velocity vs. time graphs of the buggy and cart and figured out velocities, slopes, and winners of the races. We also solved the displacement and distances of the cart and buggy races. Today we did three labs:The Stopping distance lab, the backpack lab, and the dry ice lab. In the stopping distance lab, we pushed a block of wood along the table and measured how long it took to stop and how long it was passing through the photo gate timer. We found that friction, the force of the push, the velocity and the length of the wood impacted the results. The higher the velocity, the longer it will take to stop. To find the velocity of the cart, we divided the cart's length by the time in the photogate. then we conducted the experiment and recorded the data. The experiment related to how if you are texting while driving and see something to avoid in the road, like a kid, what the distance you should allow yourself to stop depending on your current speed. The back pack lab showed that when we dropped it from a certain height, it fell at a constant rate of acceleration. The dry ice lab showed us that when it's going through sublimation, the gases coming out of the dry ice keep it off the table, causing little to no friction. This showed that it has a constant velocity and cannot stop on its own. The end