Department of Physics and Astronomy
Michigan State University
PHY231 Fall 1997

Lecture 19: October 13

Reading before class: C/J 10.1 - 10.5

Topics and Concepts

• Elastic expansion
• Shear deformation
• Volume deformation
• Stress / strain / hookes law
• Ideal spring
• Simple harmonic motion
• Elastic potential energy

Equations

• F = Y (delta L/L_0)A (elastic)
• F = S (delta x/L_0)A (shear)
• Delta P = -B (Delta V/V_0) [Delta F = -B(Delta V/V)A] (volume)
• F = -kx (restoring force of an ideal spring)
• W_elastic = 1/2 kx^2 (elastic energy)

Examples

• Expanding Steel Beam (C/J example 2, page 281)
• Jell-O (C/J example 3, page 283)
• Shorter Springs are Stiffer (C/J example 5, page 286)
• Object on a Horizontal Spring (C/J example 10, page 295)
• Changing Mass of a Simple Harmonic Oscillator (C/J example 11, page 296)

Handouts

• Homework 7

Reading for next class: C/J 10.4-10.8

PHY 231

This document http://www.pa.msu.edu/courses/1997fall/PHY231/lect19.html was last updated on 20 August 1997 by Thomas Glasmacher