throw.go

// Experimentalphysik I 2018/19: Schiefer Wurf.
// Gruppe 7
//
// (c) 2018 Lewin Bormann
package main

import (
	"flag"
	"fmt"
	"math"
)

var (
	h0   = flag.Float64("h0", 0, "h0")
	v0   = flag.Float64("v0", 10, "v0")
	beta = flag.Float64("beta", 30, "beta")
	t    = flag.Float64("t", 0.1, "delta-t")
	g    = flag.Float64("g", 9.81, "g")
)

type state struct {
	t               float64
	h, x            float64
	v_vert, v_horiz float64
}

func iterate(s state, delta float64) state {
	next := s
	next.t += delta
	next.h += delta * s.v_vert
	next.x += delta * s.v_horiz
	next.v_vert -= delta * *g
	next.v_horiz = s.v_horiz
	return next
}

func print(s state) {
	fmt.Printf("%.3f\t%.3f\t%.3f\t%.3f\t%.3f\n", s.t, s.x, s.h, s.v_horiz, s.v_vert)
}

func main() {
	flag.Parse()
	s := state{
		t:       0,
		h:       *h0,
		x:       0,
		v_vert:  math.Sin((*beta/180)*math.Pi) * *v0,
		v_horiz: math.Cos((*beta/180)*math.Pi) * *v0,
	}

	for s.h >= 0 {
		print(s)
		s = iterate(s, *t)
	}
	print(s)
}