1.  Do Now: on handout  WDYS  WDYT ▪ TB pg. 105  Agenda:  Do Now  Objective/Success Criteria  Investigate  Learning Objective:  Describe the connection among speed, friction, and radius of a curve when turning.  Success Criteria:  Recognize the need for a centripetal force when rounding a curve  Predict the effect of an inadequate centripetal force  Relate speed to centripetal force  Calculate maximum safe speed when driving on a curve

2.  In your own words…  Describe what reaction time is….How does reaction time affect driving?  Describe what benefits friction force has on driving an automobile down a road?Why?  Important upcoming dates  Quiz: Tuesday 10/4  Chapter 1 Test 10/11  Chapter Challenge Due  October 12 (Presentations)  October 5 (Class work day)

3.  Do Now:  Read through procedures #1, 2, 8-12 on pgs 105-109  Agenda:  Do Now  Objective/Success Criteria  Investigate  Learning Objective:  Describe the connection among speed, friction, and radius of a curve when turning using words and equations.  Describe the forces acting on an object traveling in a circle.  Success Criteria:  Recognize the need for a centripetal force when rounding a curve  Predict the effect of an inadequate centripetal force  Relate speed to centripetal force  Calculate maximum safe speed when driving on a curve

4.  Do Now:  Predict what will happen in Investigate #9 on pg. 107. ▪ As radius increases, maximum safe speed ___________ (increases, decreases, stays the same) ▪ As the curve in the road gets tighter, you have to ________ (slow down, speed up, go the same speed)  Agenda:  Do Now  Objective/Success Criteria  Investigate  Physics Talk  Learning Objective:  Describe the connection among speed, friction, and radius of a curve when turning using words and equations.  Describe the forces acting on an object traveling in a circle.  Success Criteria:  Recognize the need for a centripetal force when rounding a curve  Predict the effect of an inadequate centripetal force  Relate speed to centripetal force  Calculate maximum safe speed when driving on a curve

5.  What is a force?  What forces were acting on the car that makes it go in a circle?  a push or a pull

6.  Ladybug Motion Ladybug Motion

7.  Why does the car turn?  Newton’s Law: an object in motion will stay in motion in a straight line at a constant speed unless a force acts on it.  Force toward the center of the circle keeps the object moving in a circle

8.  What is centripetal force?  The force directed toward the center to keep an object moving in a circular path.  String on car  Friction between block and turntable  Friction between wheels and road

9.  What is centripetal acceleration? Remember: Speed: change in distance per unit time Velocity: change in distance per unit time in a direction. Acceleration: change in velocity per unit time Centripetal acceleration: change in direction of velocity with respect to time

10.  How do you calculate speed of a turning object?  V=d/t  Circumfrence=2∏r  V=2∏r/t

11.  A student is spinning a turntable with a wooden block resting on it. The block is located 40 cm from the center of the table and the turntable is rotating 20 times every minute. What is the speed of the wooden block on the turn table?

12. Quick Notes: How can an object accelerate with out changing it’s speed? Grab an accelerometer and see if you can accelerate while moving at constant speed. What did you do?

13. Quick Notes 14. Identify what causes the Centripetal force for the following: a) Moon revolving around Earth b) Car turning on the road c) Cork on a string d) Kid on amusement park ride

14. PTG Pg 114 #1-4