cpd_2022_energy/lib/models/EnergyBilanceModel.dart

import 'dart:math';

import 'package:flutter/material.dart';

class EnergyBilanceModel extends ChangeNotifier {

  double _startVelocity = 0;
  double _endVelocity = 0;
  double _startHeight = 0;
  double _endHeight = 0;

  double _weight = 0;

  final double _gravity = 9.81; //in m/s^2

  final double _waterHeatCapacity = 4181; //J / (kg * C°)
  final double _ironHeatCapacity = 439; //in J / (kg * C°)

  double _waterTemparatureStart = 20; //in °C
  final int _temparatureToBoilWater = 100; //in °C

  double _ironTemparatureStart = 20; //in °C
  final int _temparatureToMakeIronGlow = 700; //in °C

  double get deltaVelocity => _endVelocity - _startVelocity;
  double get deltaHeight => _endHeight - _startHeight;

  double get potentialEnergy => _weight * _gravity * deltaHeight; //in Joule = m^2 kg/s^2
  double get kineticEnergy => _weight * pow(deltaVelocity, 2) / 2;

  double get amountOfBoilingWaterInL => (((potentialEnergy + kineticEnergy) / _waterHeatCapacity) / (_temparatureToBoilWater - _waterTemparatureStart)); //in litre
  double get amountOfGlowingIronInKg => (((potentialEnergy + kineticEnergy) / _ironHeatCapacity) / (_temparatureToMakeIronGlow - _ironTemparatureStart)); //in kg

  void setStartVelocity(double v){
    _startVelocity = v;
    notifyListeners();
  }

  void setEndVelocity(double v){
    _endVelocity = v;
    notifyListeners();
  }

  void setStartHeight(double h){
    _startHeight = h;
    notifyListeners();
  }

  void setEndHeight(double h){
    _endHeight = h;
    notifyListeners();
  }

  void setWeight(double m){
    _weight = m;
    notifyListeners();
  }
}