how to make the mass m dragable n the world view in circular motion?

i seems to have encounter a problem which i need someone else to discuss with to understand why the mass cannot be drag.

in the fixed relation

x=R*Math.sin(cta);

y=R*Math.cos(cta); // jamming the on drag codes

in the object m

on drag i added these codes to execute when drag.

cta = Math.atan2(y,x);

R = Math.sqrt(x*x+y*y);

_initialize();

i don't see anything wrong with the method i used to make the mass m execute

cta = Math.atan2(y,x);

R = Math.sqrt(x*x+y*y);

but it does not work.

the remixed work is here http://www.phy.ntnu.edu.tw/ntnujava/index.php?topic=1892.0

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