11-18-08

To start class Mr. Manning used the smart board to make a graph by sliding the block away from the radar thing. He does this to prove that the pulling force is equal to the static force. Next he gave us 30 seconds to answer the daily question and then he explained it and discussed it with the class. Then we looked at a microscopic picture of friction on the sidewalk and on a smooth table. Mr. Manning then explains why it is slippery on roads when it rains, which is that it could fill in the "valleys" and make a barrier between the tires and the road. Then he made us look for a previous lap that has a slope with no units from unit 1 or 2. Rubber on concrete has the highest static and kinetic friction which is why they use rubber tires and concrete roads. Then he informs us that we will be solving problems that involve everything we have ever learned, and has us solve two problems. After we solved the first problem, we got a negative Fk because it is moving to the left. Then using the Fk we found he coefficient of friction by dividing Fk by Fn. For the last 10 minutes of class Mr. Manning had us answer the next question on page 27, the problem is the exact same problem as the daily question we did the other day with sally the swimmer. There is no homework but don't forget the test and reading guide are due friday!!!