cannon bal using appletl in java

import java.applet.Applet;
import java.awt.*;
import java.awt.color.*;
import javax.swing.*;
import javax.swing.event.*;

public class projectile extends Applet implements Runnable{

double x=0,y=0,u=110,t=0,m=40;
Thread th;
/* public void update (Graphics g)
{
paint(g);
}*/
public void paint(Graphics g)
{
setBackground(Color.yellow);
g.setColor(Color.BLUE);
g.fillOval((int)x, (int)y, 50, 50);
g.fillRect(0,500,1300,10);
}
public void init(){
setSize(1500,600);
}
public void start()
{
th=new Thread(this);
th.start();
}
public void run() {
double T=0;
while(t<=T)
{
m= Math.toRadians(m);
T=2*u*(Math.sin(m))/9.8;
x=100+u*(Math.cos(m))*t;
if(t<T/2)
y=500-(u*t*(Math.sin(m))-(0.5)*9.8*t*t);
else if(t>T/2)
y=500-(u*t*(Math.sin(m))-(0.5)*9.8*t*t);
else
y=y;
repaint();
m=Math.toDegrees(m);t=t+0.01;
try
{
Thread.sleep(4);
}
catch(InterruptedException ex)
{
}


}
}
}