http://www.physicsclassroom.com/class/sound/Lesson-4/Forced-Vibration [2]
http://www.met.reading.ac.uk/pplato/resources/h-flap/p5_3t.pdf [3]
http://en.wikipedia.org/wiki/Vibration [4]
http://www.math.utah.edu/~gustafso/f2009/forcedVibrationsResonance2008.pdf [5]
http://www.newagepublishers.com/samplechapter/000591.pdf [6]
http://www.britannica.com/EBchecked/topic/213174/forced-vibration [7]
Links
[1] https://hootsgo.org/?q=node/6424
[2] http://www.physicsclassroom.com/class/sound/Lesson-4/Forced-Vibration
[3] http://www.met.reading.ac.uk/pplato/resources/h-flap/p5_3t.pdf
[4] http://en.wikipedia.org/wiki/Vibration
[5] http://www.math.utah.edu/~gustafso/f2009/forcedVibrationsResonance2008.pdf
[6] http://www.newagepublishers.com/samplechapter/000591.pdf
[7] http://www.britannica.com/EBchecked/topic/213174/forced-vibration