1. LUG and test review Monday, October 6, 2014

2. Monday, 10/6 Unit 3: Work and Forces  Pick up warm-up sheet from Physics bin  Write the question in the box for today and answer it. If you need more room write it on the back. You have 3 minutes to complete.  I will collect the weekly warm up sheets at the end of the week.  Read the ‘I can’ statements on the side board.  Review dates below  Upcoming dates  Wednesday, 10/8 – quiz  Wednesday, 10/8 – Mrs. Cheyne will not be at school  Friday, 10/10 – Unit 3 test  Friday, 10/24 – last day to turn in 2SW extra credit  Friday, 10/31 – end of 2SW

3. Warm- up 1. A rock with a mass of 5 kg is attached to a string and a child is applying an upward force to the string. Use the diagram below determine the Net Force. Fg = 49 N Ft = 15 N 2. A rock with a mass of 5 kg is attached to a string and a child is applying an upward force to the string. The rock is accelerating 6.8 m/s 2 downward. Calculate the net force and determine the F T on the string. Fg = 49 N Ft = _____

4. Law of Universal Gravitation

5. Video  http://dsc.discovery.com/videos/assignment- discovery-shorts-newtons-explanation-of- gravity.html http://dsc.discovery.com/videos/assignment- discovery-shorts-newtons-explanation-of- gravity.html

6. Take LUG notes

7. Review Equation  What does the G in the equation mean? Will it ever change?  Describe the relationship between mass and distance between the objects.  What variable has greatest role in evaluating the force of gravity between objects? Support your answer

8. Practice Problem 1 Tom has a mass of 70.0-kg and Sally has a mass of 50.0-kg. Tom and Sally are standing 20.0m apart on the dance floor. Sally looks up and sees Tom. She feels an attraction. If the attraction is gravitational, find its size. Assume that both Tom and Sally can be replaced by spherical masses.

9. Practice Problem 2  What is the gravitational attraction between two spheres ( m sphere = 1.67 X 10 -27 kg) at a distance of 5.0 X 10 -15 m? 7.44 x10 -36 N

10. Practice

11. Reveiw