Resonance Lecture 32 November 21, 2008

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

Workbook Problems due Friday Problems 14-1 through 8, pages 14-1 -- 5

Energy in Simple Harmonic Motion

Pendulum Point mass on a string

Physical Pendulum d L Center of gravity θ

Damped Harmonic Motion Friction rears its ugly head!

Damped Harmonic Motion

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?

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

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?

Problem 14.30

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

Problem 14.33

The period of this oscillator is approximately

The period of the oscillator is

The is zero at t = ?? approximately

The velocity is zero when t =

The acceleration is a maximum when t = ??

The acceleration is max when t= None of the above

The velocity is a maximum for t = ??

The velocity is a maximum for t =

Problem 14. 37 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?

Problem 14.37

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?

Problem 14.32

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