Thread: Need help with while loop

Ok so I attatched the assignment the question I'm on is #2 and this is what I have down so far. It asks for a return type but I'm not sure what to return? Any advice would be greatly appreciated I've been working on this assignment for what seems like forever.

public class cannonball
{
    private double velocity;
    private double time;
    final double GRAVFORCE = 9.81;
    private double height;
    private double heightFormula;
    private double maxHeight;
 
    public cannonball(double Velocity)
    {
        velocity = Velocity;
        height = 0;
        heightFormula = 0;
    }
    public double simulateFlight()
    {
      time = 0;
        while(height>0||time<100)
        {
            heightFormula = (velocity*time)-0.5*GRAVFORCE*Math.pow(time,2);
            height = velocity*time;
            time++;
            velocity = velocity - GRAVFORCE*time;
            str = time + "\t\t"+ velocity +"\t\t" + height + "\t\t"+ heightFormula;
        }
 
    }
}