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 Author Topic: A pendulum connected to a spring  (Read 15554 times) 0 Members and 1 Guest are viewing this topic. Click to toggle author information(expand message area).
concord
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 « Embed this message on: August 21, 2005, 08:09:59 pm »

A pendulum connected to a spring:

http://mw.concord.org/modeler1.3/mirror/mechanics/pendulum3.html

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Fu-Kwun Hwang
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 « Embed this message Reply #1 on: February 17, 2010, 04:35:53 pm » posted from:Taipei,T\'ai-pei,Taiwan

The following is an EJS version of the above applet (with more options)

You can drag the spring, particle and the rod with mouse click/drag.
You can change spring constant k, mass m , spring length L, and damping constant b.
Enjoy it!

Embed a running copy of this simulation

Embed a running copy link(show simulation in a popuped window)
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• Please feel free to post your ideas about how to use the simulation for better teaching and learning.
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• Upload worksheets as attached files to share with more users.
Let's work together. We can help more users understand physics conceptually and enjoy the fun of learning physics!
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Fu-Kwun Hwang
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 « Embed this message Reply #2 on: October 24, 2011, 12:51:49 pm » posted from:Taipei,T'ai-pei,Taiwan

Equation used in the above simulation.
Assume angle $\theta$ for the pendulum, angular velocity $\omega=\frac{d\theta}{dt}$
And $\frac{d\omega}{dt}=calAplha(\theta)+ g\cos\theta+ -b\omega/m$
where $caAplha(\theta)$ calculate spring force and find it tangential component.

Code:
public double calAlpha (double c) {
cs=Math.cos(c);
sc=Math.sin(c);
x=x2-R*cs;
y=y2-R*sc;
L=Math.sqrt((x-x1)*(x-x1)+(y-y1)*(y-y1));
f=-k*(L-L0); fx=f*(x-x1);
fy=f*(y-y1);
n=-fx*cs-fy*sc;
nx=-n*cs;
ny=-n*sc;
fx=fx-nx;
fy=fy-ny;
if(c>0)sign=-1;
else sign=1;
return sign*Math.sqrt(fx*fx+fy*fy)/I; // where I is the momentum of initial
}
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Life is an inspiration. ..."Mahatma Gandhi(1869-1984, The greatest leader of modern India)"