# Example:
Spring-mass system

A mass suspended from a spring, displaced vertically and released
to move freely to produce up and down motion

The model view
of a mass suspended from a spring, displaced vertically and
released to move freely to produce up and down motion with right
panel showing the displacement, velocity and acceleration.

## Q1:
under what conditions would this vertical spring mass system’s
motion be not well modeled as a simple harmonic motion?

H1: the model assumes the restoring force by the spring is F =
-ky, it is always correct for any magnitude of oscillation y in
real springs. Is it always valid in the real spring motion when
the spring is hyper extending beyond the linear limits of Hooke's
Law ?

## Q2:
change the simulation y=0 m and Play the model. In the your model
Y = _________, suggest your own suitable model that can describe
the motion y.

## Q3:
in this same motion, propose the velocity and acceleration
model(s)

## Q4:
carry out some other conditions, verify that the general equations
for displacments if can be model by Y = Y_{0}sin(ωt+φ)+Y_{shift} where the usual
symbols have the usual meaning. Hence or otherwise, Suggest with
reasons, the meaning of Y_{0} , ω , φ , and Y_{shift}.

## Q5:
similarly, suggest whether the model(s) for velocity, v_{Y} =ωY_{0}cos(ωt+φ)
and

## a_{Y} = - ω^{2}Y_{0}sin(ωt+φ).
Test them out using an example of your choice.

## Youtube

http://youtu.be/P-Umre5Np_0 MIT
Physics Demo -- Spray Paint Oscillator. A can of spray paint is
attached to a spring oscillator. A roll of paper is run past the
oscillating can. The result is a sine wave -
http://en.wikipedia.org/wiki/Sine_wave - on the paper.Watch the
original video on MIT TechTV -http://techtv.mit.edu/videos/803-spray-paint-oscillator

## Tracker
activity:

http://weelookang.blogspot.sg/2012/08/tracker-modeling-in-spring-mass-system.html

## Run
Model:

https://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHM16_1/SHM161_Simulation.xhtml

backup

http://dl.dropboxusercontent.com/u/44365627/lookangEJSworkspace/export/ejss_model_SHM02/SHM02_Simulation.xhtml