Get Velocity And Position Of A Projectile

Use Java, physics and simple math to calculate the position of a projectile at a given time and its velocity.

On Thursday, August 7th 2008 at 04:51 PM

By Andrew Pociu (View Profile)

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import java.awt.Point;
 
public class Projectile 
{
        double angle;
        double initialVelocity;
        Point initialPoint;
 
        public Projectile(Point initPoint, double angle, double initialVelocity)
        {
                this.angle = angle;
                this.initialVelocity = initialVelocity;
                this.initialPoint = initPoint;
        }
        
        private double getHorizontalVelocity(double angle, double velocity)
        {
                return Math.cos(Math.toRadians(angle)) * velocity;
        }
        
        private double getVerticalVelocity(double angle, double velocity)
        {
                return Math.sin(Math.toRadians(angle)) * velocity;
        }
        
        public Point getPositionAt(double time)
        {
                double x = getHorizontalVelocity(angle, initialVelocity) * time;
                double y = getVerticalVelocity(angle, initialVelocity) * time - 0.5 * (9.8 * time * time);
                Point currPoint;
                currPoint = new Point(
                                (int)Math.round(x) + initialPoint.x, 
                                (int)Math.round(y) + initialPoint.y);
                return currPoint;
        }
        
        public static void main(String args[])
        {
                Projectile ball = new Projectile(new Point(0,0), 35.0, 40.0);
                System.out.println(ball.getPositionAt(0));
                System.out.println(ball.getPositionAt(2));
                System.out.println(ball.getPositionAt(5));
        }
}