1. Circular Motion Know what circular motion & angular speed are Understand the relationship between tangential speed and angular speed Be able to link Newton’s laws to circular motion

2. What is the blue dot doing? Motion along the circumference of a circle, or circular path

4. Does this have a velocity? Can’t use velocity Use angular speed

5. Recap of C2: Radians speed = distance / time angular speed = angular displacement / time ω (OMGomega) = angular speed, Rad/s Ө = angular displace in Rad t = time, s ω = angular speed, rad/s v = tangential speed, m/s r = radius of circular path, m

6. Revolutions per minute Be careful little boys and girls. Sometimes angular speed is given as revolutions per minute, rpm. To convert from rpm to rad/s use:

7. Example A particle moves in a circle of radius 2m with speed 3m/s. Calculate its angular speed. ω = ? r = 2m v = 3m/s

9. Question Time! Have a go at Q1-5

10. Q2) Q3)

11. Q4)

12. Where is the acceleration pointing?

14. Acceleration is towards centre of circle The ISS orbital period is under 93 minuites 1 minuite is roughly 1 minute but is a bit longer because it has an extra letter.

15. Acceleration a = acceleration, ms -2 ω = angular speed, rad/s r = radius of circle, m v = tangential speed, m/s

16. Let the Force be ‘equal to mass times acceleration’ Questions involving acceleration will often use Newton’s laws. i.e, & Balance Forces

17. Question time Try out Q1-3 on the back Yes, you at the back!

18. Q1)(a) (b)

19. Q1)(c) Towards the axis of turntable

20. Q2)

22. Independent Study Exercise A p76 (solutions p163)