Mechanical Waves
Harmonic Motion
Harmonic Motion
What makes things oscillate?
Work = Force * distance
Consider extended spring: Stored energy
release spring --> oscillation
Motion oscillates between
stored energy and energy of motion
==> transfer of energy
constant K depends on spring material
Time for 1 cycle : T[period]
Frequency :
Unit is Hertz : [Hz] = [1/s]
named after Heinrich Hertz (1857 - 1894); University of Bonn (Germany)
See the animation Circles and Sine Waves .
REVIEW
Why do things oscillate?There is a restoring force F = -kxEnergy is stored. Recall: Energy = Work = F d
Oscillation results from energy transfer
. stored energy --> Energy of motionEnergy of motion --> stored energy
Period T : time for one
full cyclefrequency f: f = 1/T Example : An oscillator takes 0.1 s for 1 cycle.
--> f = 1 / 0.1 s = 10 Hz
Ch. ElsterAug 26 14:27:03 EDT 2019