1. Resonance
Lecture 32
November 21, 2008

2. Robert Hooke “ceiiinosssttuv” Anagram for “ut tensio, sic vis”
“as the extension, so the force”

3. Workbook Problems due Friday
Problems 14-1 through 8, pages

4. Energy in Simple Harmonic Motion

5. Pendulum
Point mass on a string

6. Physical Pendulum d L
Center of gravity θ

7. Damped Harmonic Motion
Friction rears its ugly head!

8. Damped Harmonic Motion

9. Problem 14.15
A) When the displacement of a mass on a spring is ½A, what fraction of the mechanical energy is kinetic energy and what fraction is potential?

10. B) At what displacement as a fraction of A, is the energy half kinetic and half potential?

11. Problem 14.30
The center of gravity of a lower leg of a cadaver which had a mass of 5kg was located 18cm from the knee. When pivoted at the knee , the oscillation frequency was 1.6Hz. What is the moment of inertia of the lower leg?

12. Problem 14.30

13. Problem 14.33
The amplitude of an oscillator decreases to 36.8% of it initial value in 10.0s. What is the time constant?

14. Problem 14.33

15. The period of this oscillator is approximately

16. The period of the oscillator is

17. The is zero at t = ?? approximately

18. The velocity is zero when t =

19. The acceleration is a maximum when t = ??

20. The acceleration is max when t=
None of the above

21. The velocity is a maximum for t = ??

22. The velocity is a maximum for t =

23. Problem
A 25 kg child sits on a 2.0m long rope swing. To maximize the amplitude of the swinging, how much time should be between pushes?

24. Problem 14.37

25. Problem 14.32
A thin, circular hoop with a radius of 0.22m is hanging from its rim on a nail. When pulled to one side and released, the hoop swings back and forth. The moment of inertia for a hoop with the axis passing through the circumference is I = 2MR2. What is the period of oscillation?

26. Problem 14.32

27. Exam IV Wednesday, December 3
Chapter 10 and 14
Quick Review Monday