The document discusses circular motion and Newton's laws of motion. It covers topics like circular motion in horizontal circles, vertical circular motion using a bucket of water as an example, and loop the loops. Newton's laws state that an object will remain at rest or in uniform motion unless acted on by an external force, acceleration is proportional to force, and for every action there is an equal and opposite reaction. Circular motion concepts like centripetal force, acceleration, and how tension provides the centripetal force in different situations are also examined.

1. Physics Cir cu lar Mo tion

5. No external force The body remains at rest. The body moves with a constant speed . Newton’s first Law

7. For fixed force A body with a larger mass moves with a smaller acceleration . A body with a smaller mass moves with a larger acceleration . Newton’s second Law

8. For fixed mass A body with a smaller net force moves with a smaller acceleration . A body with a larger net force moves with a larger acceleration . Newton’s second Law

10. Body A exerts a force on body B, then body B exerts an equal and opposite force on body A. Newton’s third Law Body A Body B Force on B by A Force on A by B

11. Newton’s third Law

12. Circular Motion in horizontal circles

13. Circular Motion in horizontal circles Angular velocity  =  / t Linear velocity v =  r Centripetal force F = m r  2 = m v 2 / r Centripetal acceleration a = r  2 = v 2 / r

14. Circular Motion in horizontal circles Conical pendulum

15. Circular Motion in horizontal circles Conical pendulum Do you remember what kind of forces provides the centripetal force to the bob ? Tension T Weight mg Centripetal force

16. Vertical circular motion Bucket and water Does the water spill out the bucket when whirling ? If no, why doesn’t it spill out ?

17. Vertical circular motion Bucket and water What kind of motion does the bucket perform ? Vertical circular motion What kind of force provides the centripetal force F c to the bucket ? Tension T Weight mg

18. Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the highest position ? F c = T + mg Tension T Weight mg

19. Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the lowest position ? F c = T - mg Tension T Weight mg

20. Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the water at the highest position ? F c = R + W Reaction of the bucket R Weight of water W

21. Vertical circular motion Bucket and water What kind of force provides the centripetal force F c to the bucket at the lowest position ? F c = R - W Reaction of the bucket R Weight of water W

22. Vertical circular motion Loop-the-loop

23. Vertical circular motion Loop-the-loop What kind of force provides the centripetal force F c to the mass ? The reaction of the track

24. Class exercises M.C. Exercise Main menu True or False

29. You are wrong. Try again ! Sorry ！ return

30. Congratulation ! Correct ! Return