Use this as a hint…

2. Use this as a hint… • http://phet.colorado.edu/en/simulation/ladybug-motion-2d

3. #1. The ladybug moves CLOCKWISE. What could the FORCE and VELOCITY vectors, respectively, look like?

4. Do Now Answers #1. The ladybug moves CLOCKWISE. What could the FORCE and VELOCITY vectors, respectively, look like? (A, B, C, or D) Velocity is a straight line TANGENT to the circle Force is directed INWARD at a right angle to velocity Answer is C

5. #2. The ladybug moves CLOCKWISE. What could the ACCELERATION and VELOCITY vectors, respectively, look like?

6. Do Now Answers #2. The ladybug moves CLOCKWISE. What could the ACCELERATION and VELOCITY vectors, respectively, look like? (A, B, C, or D) Velocity is a straight line TANGENT to the circle Acceleration is directed INWARD at a right angle to velocity Answer is C

7. Do Now Answers #3. The ladybug moves COUNTERCLOCKWISE. Draw and Label the FORCE, ACCELERATION, and VELOCITY vectors. Velocity is a straight line TANGENT to the circle Acceleration & Force Are both directed INWARD at a right angle to velocity

8. #4. Imagine the bugs are attached to a bar as shown. What would the TANGENTIAL VELOCITY vectors look like at points X & Y?

9. Do Now Answers #4. Imagine the bugs are attached to a bar as shown. Bug X has a larger tangential speed; Bug Y has a smaller tangential speed; Answer must be B!

10. CHECK QUESTION!! Imagine the bugs are attached to a bar as shown. Which bug has the larger ROTATIONAL VELOCITY? • Bug X • Bug Y • Not enough info to say • Same

11. #5. Imagine the bugs are attached to a bar as shown. What would the ACCELERATIONvectors look like at points X & Y?

12. Do Now Answers #5 & 6!!!! Both bugs must have INWARD directed forces, And therefore inward directed accelerations!

13. POGIL Review • Turn to the summary portion at end of POGIL. • 5 minutes to complete #1-8 • We will we clicking in as a class

14. 1. The force that causes an object to move in a circular path acts… • Inward, towards the center • Curved, In a circle • Tangent • Curved, away from the circle • Outward, away from the center • None of the above

15. 2. If you were to remove that force from the object, the object would take a path that looked like • Inward, towards the center • Curved, In a circle • Tangent • Curved, away from the circle • Outward, away from the center • None of the above

16. 3. You are traveling in the passenger seat of a car. All of the sudden, the driver makes a sharp LEFT turn. Do you feel as if you are moving to the right, or the left? • Right • Left • Neither

17. Imagine that you are a passenger in a car which is making a left turn. • As the car begins to take the turn to the left, you often feel as though you are sliding to the right. • The car is turning to the left due to the inward CENTRIPETAL force, yet you feel as though you are being forced rightward or outward. • In actuality, the car is beginning its turning motion (to the left) while you continue in a straight line path. This motion can be better understood by examining the animation below. • http://www.physicsclassroom.com/mmedia/circmot/rht.cfm • http://www.mrwaynesclass.com/teacher/circular/CarAndCurve.htm

18. 4. When a car travels in a circular path, what force holds the car in the curved path? (Hint: Is it easy to maneuver a car when road conditions are icy?) • Gravity • Support force • Centrifugal force due to friction • Centripetal force due to friction

19. 5. Please answer the following question: When riding the “Himalaya” or “Music Express” carnival rides, is it more comfortable to sit on the outside seat or the seat closer to the center? Why? • Outside seat • Inside seat • Doesn’t matter

20. 5. Please answer the following question: When riding the “Himalaya” or “Music Express” carnival rides, is it more comfortable to sit on the outside seat or the seat closer to the center? Why?http://www.youtube.com/watch?v=DtNVLEXzcvM

21. 6. Suppose you were to let go of the string holding the water bottle. (DO NOT DO THIS) What path would the water bottle follow? • Inward, towards the center • Curved, In a circle • Tangent • Curved, away from the circle • Outward, away from the center • None of the above

22. 7. Picture a washing machine drum. It rotates, and has holes in the side of the drum. Is the water being forced away from the clothes, or are the clothes being forced away from the water? • The water is being forced away from the clothes • The clothes are being forced away from the water • Neither the clothes nor water are being forced • Both the clothes and water are being forced

24. 8.  Explain why various race tracks have banked curves – or inclined walls.http://www.youtube.com/watch?v=HmFMAGxGavY • More centripetal force • Less centripetal force • More centrifugal force • Less centrifugal force

25. Concept Development • On the back of your Study Guide • Complete this! • We are going over this in 5 minutes!

26. Remember – YOU want to move according to Newton’s 1st Law – no change in motion. Only a FORCE will change your motion. Remove the force (in this case, back of seat), you tend to stay at rest.

27. Remember – YOU want to move according to Newton’s 1st Law – no change in motion. Only a FORCE will change your motion. Remove the force (in this case, seatbelt), you tend to keep a constant velocity.

28. Remember – YOU want to move according to Newton’s 1st Law – Straight line, same speed. Only a FORCE will change your motion. Remove the force (in this case, seatbelt and car door), you tend to keep a constant, TANGENT velocity – you would fly out of the car by virtue of your inertia, since there would be NO force on you!

29. **Summary** • CENTRIPETAL force is always inward, towards the center of the circle. (So is the acceleration! Object is changing direction, so its velocity is changing, so it is accelerating INWARD just like the force!) • CENTRIPETAL force causes objects to MOVE in a circular path • CENTRIFUGAL is the FEELING of being thrown outward (due to INERTIA / 1st Law), but it is not a real force! There is NEVER a force that throws you “outward” • When you turn, CENTRIPETAL force keeps you turning. Remove the force, you move in a tangent path because there is NO FORCE acting on you – you move by virtue of your own inertia / Newton’s 1st Law!

30. Concept Development • On the back of your Study Guide • Complete this! • Check in w/ teacher to review (you WILL see this on your test) • Then, you will receive a Web Quest…. • You have the rest of class to prep for your quest by completing the… • Web Quest (not collecting or grading…but some of the questions will be on your Quest) • Study Guide (not collecting or grading…but some of the questions will be on your Quest) • Tonight’s HW (#13-15, 3 points)

31. At this time… • Return your CLICKERS! • You have the rest of class to prep for your quest by completing the… • Web Quest (not collecting or grading…but some of the questions will be on your Quest) • Study Guide (not collecting or grading…but some of the questions will be on your Quest) • Tonight’s HW (#13-15, 3 points) • Next class we will… • Review HW #8-15 • Take the quest • Start Ch. 12 (Big Bang, Black Holes, Universal Gravitation)