// Marty Stepp, CSE 142, Autumn 2008
// This program displays the motion of a thrown projectile over time.
// (The program is unfinished for now.)

public class Projectile {
	public static void main(String[] args) {
		projectile(60, 50, 10);
		projectile(50, 80, 50);
	}
	
	// Plots the motion of a single projectile with the given
	// initial velocity v0, angle, and number of steps to plot.
	public static void projectile(double v0, double angle, int steps) {
		// v0y = v0 sin theta
		// t = -2v0 / a
		double v0y = v0 * Math.sin(Math.toRadians(angle));
		double v0x = v0 * Math.cos(Math.toRadians(angle));
		double totalTime = -2 * v0y / -9.81;
		double dt = totalTime / steps;
		
		// print the position at each time step
		for (int i = 0; i <= steps; i++) {
			double t = i * dt;
			double x = v0x * t;
			System.out.println(x + "    " + t);
		}
	}
	
	// Computes how far a body has moved given an initial velocity v0,
	// force a, and time t.
	public static double displacement(double v0, double a, double t) {
		return v0 * t + 0.5 * a * Math.pow(t, 2);
	}
}