1. Quiz, Elastic PE, Power Thursday, September 11, 2014

2. Thursday, 9/11 Unit 2: Work, Power, and Energy  Pick up a calculator or take out your calculator for the quiz.  Pick up a red pen (by the black trays)  Take out your homework from Tuesday.  Upcoming dates  ‘A’ day Unit 2 test – Wednesday, 9/17  Last day to turn in 1SW extra credit – Friday, 9/19

3. Review homework

4. Quiz  Take out your Energy notes, homework, practice problems, etc.  All phones need to be in your bag (don’t have a bag…put it on my desk)  Remember phone out during a quiz/test = cheating no questions asked.  When you are done with quiz flip your paper over so I know you are done. The quiz will end 15 minutes after we begin.

5. Elastic Potential Energy  Read the information about potential energy  During your second reading, highlight the following words:  Spring  Elastic  Energy  Potential energy  Stretch  Compress  Force  Spring constant  Equilibrium position

6. Elastic Potential Energy Example A plastic bullet with a mass of.45 kg is put into a toy gun. The spring in the gun has a spring constant of 200 N/m. The spring is compressed.20 meters before the bullet is released. What is the potential energy of the bullet before the trigger is pulled?

7. Practice problem 1 A plastic bullet with a mass of.20 kg is put into a toy gun. The spring in the gun has a spring constant of 100 N/m. The spring is compressed 4.0 x 10 -3 meters before the bullet is released. What is the potential energy of the bullet before the trigger is pulled?

8. Practice problem 2 A plastic bullet with a mass of.35 kg is put into a toy gun. The spring in the gun has a spring constant of 300 N/m. The spring is compressed 6.0 x 10 -3 meters before the bullet is released. What is the potential energy of the bullet before the trigger is pulled?

9. Power in Physics  Is a measure of how much work you do in a certain amount of time.  Remember W = F x d  The relationship of power can be analyzed by using the following equation: