On the Curves

# On the Curves

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## On the Curves

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1. On the Curves Section 4.6

2. Investigate: Part A Toy Car with String • What kept it moving in a circle? • What happened when you let go of the string? • Which way did the string pull?

3. Investigate: Part A Car on Road • What keeps it moving in a circle? • Which way would it move if nothing keeps it moving in a circle?

4. Investigate: Part A Car on Road • Vectors

5. Investigate: Part B What happened as you spun the stopper faster? What happened as you made the string shorter? What happened when you added more mass?

6. Investigate: Part C Fc = mv2/R Fc: Centripetal Force m: Mass v: Velocity R: Radius

7. Investigate: Part C The gentler the curve, the _____ the force required to keep the car moving along the curve. If the curve is tight (R is very small) then a _____ is required

8. Physics Talk Centripetal Force and Newton’s First Law Centripetal Force and Newton’s Second Law

9. Physics Talk How to find acceleration of an object moving in a circle a = v2/R

10. Physics Talk What keeps an object moving in a circle?

11. Vocabulary Centripetal Force – a force directed towards the center that causes an object to follow a circular path.

12. Vocabulary Centripetal Force: Practice A roller coaster car is traveling east at 20 m/s. After 16 s, it is traveling north at 20 m/s. The circular curve had a radius of 200 m. Calculate the acceleration of the car.

13. Physics Talk Centripetal Force • When you held the string of the toy car? • When a roller coaster car is upright? • When a roller coaster car is tilted? • When a car is on the road?

14. Physics Talk Centripetal Force • IT IS NOT AN ADDITIONAL FORCE!!!

15. Physics Talk Centripetal Force

16. Physics Talk Three Locations used for summarizing forced and weight Constant speed:

17. Physics Talk Three Locations used for summarizing forced and weight Net force at bottom of loop:

18. Physics Talk Three Locations used for summarizing forced and weight Net force at top of loop:

19. Physics Talk Clothoid loop - a loop with a big radius at the bottom and a small radius at the top

20. Physics Talk Clothoid loop: WHY?!

21. Physics Talk SAFETY!!! What is the cutoff for “g’s”? WHY?!