October 22, 2009

Today in class we started by talking about why it was easier to draw a acceleration vs. time graph, when starting with a velocity vs. time graph, than drawing a position vs. time graph. We concluded that it was easier because when you are drawing an x vs. t graph you have to think backwards. After that we watched a short video on working in space. The astronauts were having trouble working outside of the space shuttle because of Newton's second law. It states that for every action there is an equal and opposite reaction. When the astronauts were in space there is not any gravity to anchor them to any surface. On earth we are always touching the ground creating a base for us. When the astronauts would try to spin a wheel, they would spin in the opposite direction, making work almost impossible. Since then they have found ways for the astronauts to anchor themselves on the space shuttle. The next blogger will be Melissa.

Wednesday, Sept 16

Today in class we took a reassessment. Then we walked through the Speeding up and Slowing Down sheet as a class and got that done. Then we did the Exploring the Physics of Distracted Driving lab, where we tested our reaction times on the computer and typed up our data on a google spreadsheet. Then we worked on the lab some more.

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

Thursdays Class

Thursdays class was the most important class we've ever had. We went over the history of grades and school, and we went through the process of assessing in Mr. Burk's class. Then we received our assessments and talked about them. The most we could have gotten on any concept was 3/4 and to show our full understanding, we will be assessed at the beginning of most classes until we have covered all of the concepts.

8/26/09 Class Notes

In class today, we used the ticker timer to find the average velocity of the buggy. The velocity of the buggy is uniform. The ticker timer makes 60 dots per second. We used the ticker timer and a ruler to find the the time and distance between the dots. In order to find the average velocity, you must divide the distance by the time (change in x by the change in t). The average velocity was 0.7 cm / 0.016 s = 43 cm/s. 43 cm/s * 10 s = 4.3 m. Velocity = 43 cm/s and change in time = 20 seconds round-trip. How far did the buggy travel in total? (v * change in time) = 43 * 20 = 860 cm. We also discovered that distance = (change in time / 2) * velocity or
distance = (velocity * change in time) / 2.