# NTNUJAVA Virtual Physics LaboratoryEnjoy the fun of physics with simulations! Backup site http://enjoy.phy.ntnu.edu.tw/ntnujava/

## Easy Java Simulations (2001- ) => Dynamics => Topic started by: Fu-Kwun Hwang on July 26, 2007, 11:35:20 pm

 Title: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: Fu-Kwun Hwang on July 26, 2007, 11:35:20 pm Objective9745 H2 PHYSICS (2008) 8. Oscillations Damped and forced oscillations: resonance (k) describe graphically how the amplitude of a forced oscillation changes with frequency near to the natural frequency of the system, and understand qualitatively the factors which determine the frequency response and sharpness of the resonance.Make Learning Deep and Sense MakingResonanceFor a forced oscillation, when the driving frequency is equal to the natural frequency of the oscillating system, maximum energy is transferred from the periodic force (driver) to the oscillating system which will vibrate with maximum amplitude. This phenomenon is called resonance.Frequency Response Graph (under different degrees of damping)The Effect of Damping on Forced OscillationsWhen damping is present, it reduces the amplitude (y-axis) of the forced oscillation for all driver frequencies (x-axis) and it causes the maximum amplitude to be reached when the driving frequency is a little less than the natural frequency.This reduction in amplitude is more significant at the resonance frequency and frequencies close to it, so that we say damping reduces the sharpness of resonance -- that is, the oscillating system responses little (small change in the amplitude) over a wide range of frequencies.This Interactive Resource was designed by: Wee Loo Kang Using Easy Java Simulation by : Francisco Esquembre Thanks to Fu-Kwun Hwang & Francisco Esquembre for their expert advise in (EJS):Using Forum on EJS:http://www.phy.ntnu.edu.tw/ntnujava/index.php Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 26, 2007, 11:52:53 pm i had this situation too when i publish htmlProf. Hwang, can resize the applet to maybe smaller? the plot buttton is hidden ?width="750" height="550" to fit into firefox browser. Thanks  ;D Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: Fu-Kwun Hwang on July 27, 2007, 08:27:46 am I have to modify the source to change the view to make it really work.I hope the latest version is what you want. Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 27, 2007, 09:10:07 am b = 0 frequency response no damping Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 27, 2007, 09:23:34 am b = 0.1moderate dampingmaybe (0.2, 0.4~) is an anonymous data !!?redo to verify it yourself and replot Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 27, 2007, 09:33:29 am b=0.05light damping Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 27, 2007, 09:39:48 am b=0.5heavy dampingnote that the scale for the y axis is differentcombine the graph into a common scale with get something likethe time to do these activities may be very long, some may argue no efficient for learning purpose.I would argue for a compromise, let students engage in some activity (length of doing depends on foundation of learners) and move on to synthesis of the BIG picture Title: Re: Oscillations Damped and forced oscillations by Wee Loo Kang Post by: lookang on July 27, 2007, 09:54:35 am my source ;DProf.Hwang, the copy on the forum seems to be NOT plotting the frequency response. Is my version more suitable where the applet is used as a cognitive tool for users to "conclude patterns"  :D