/* From: "COMPUTATIONAL PHYSICS, 2nd Ed" 
	 by RH Landau, MJ Paez, and CC Bordeianu 
	 Copyright Wiley-VCH 2007.
	 Electronic Materials copyright: R Landau, Oregon State Univ, 2007;
	 MJ Paez, Univ Antioquia, 2007; and CC Bordeianu, Univ Bucharest, 2007.
	 Support by National Science Foundation															 
	 */
//	 Moon.java:	moon orbiting a planet

import ptolemy.plot.*; 

public class Moon {	 
	
	public static void main(String[] argv) {	
		
		double Radius, wplanet;			   // Planet's orbit r, ang. velocity
		double radius, wmoon;							  // Moon's r, omega wrt planet
		double time, x, y;											   // Position(t) of moon
		
		Radius = 4. ;																						// Planet
		wplanet = 2. ;																 // Omega of planet
		radius = 1. ;																	  // Moon's orbit r
		wmoon = 14. ;														 // Oemga moon wrt planet
		Plot myPlot = new Plot(); 
		myPlot.setTitle("Motion of a moon around a planet "); 
		myPlot.setXLabel(" x"); 
		myPlot.setYLabel(" y"); 
		                                                         // Orbit
		for ( time = 0. ; time < 3.2; time = time + 0.02)	 {	 
			x = Radius *Math.cos(wplanet*time)+radius*Math.cos(wmoon*time); 
			y = Radius *Math.sin(wplanet*time)+radius*Math.sin(wmoon*time); 
			myPlot.addPoint(0, x, y, true);	 
		}
		PlotApplication app = new	 PlotApplication(myPlot); 
	}
}