phy53 lecture			dr. brown		18 november 2010

sho treated
  spring mass (frictionless)
  small angle pendulum

torsional spring --
 \tau = - k \theta   torque = - constant * angle of twist = I \alpha

get SHO diffy q !


physical pendulum -- 
  hoop swinging about pivot on the top of the hoop

rod swings with pivot about end
  compared to walking -- modeling a leg with rod [foot at end] pivoted at hip

note the "process" for all these SHO problems

discussion of initial conditions -- addressing question(s)

physics as gardening or cooking...

neat coordinate change to transform non-homogeneous diffy q to homogenous diffy q about equilibrium position

now -- mass on spring inserted into fluid [damping force] --- leads to damped harmonic oscillator

underdamped, critically damped, overdamped

real life -- shock absorbers in car -- "good" = slightly underdamped

next driven harmonic oscillators