Chapter 2 Question 2.10, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

(Science: calculating energy) Write a program that calculates the energy needed to heat water from an initial temperature to a final temperature. Your program should prompt the user to enter the amount of water in kilograms and the initial and final temperatures of the water. The formula to compute the energy is  

Q = M * (finalTemperature – initialTemperature) * 4184 

where M is the weight of water in kilograms, temperatures are in degrees Celsius, and energy Q is measured in joules.

import java.util.Scanner;

public class Exercise_02_10 {

    public static void main(String[] args) {

        Scanner input = new Scanner(System.in); // Create new Scanner object.

        // Prompt the user to enter the amount of water in kilograms.

        System.out.print("Enter the amount of water in kilograms: ");

        double kilograms = input.nextDouble();

        // Prompt the user to enter the initial temperature.

        System.out.print("Enter the initial temperature: ");

        double initialTemperature = input.nextDouble();

        // Prompt the user to enter the final temperature.

        System.out.print("Enter the final temperature: ");

        double finalTemperature = input.nextDouble();

        // Calculate the energy

        double energy = kilograms * (finalTemperature - initialTemperature) * 4184;

        // Display result

        System.out.println("The energy needed is " + energy);

    }

}