2.10（科学：计算能量）编写程序，计算将水从初始温度加热到最终温度所需的能量。程序应该提示用户输入水的重量（以千克为单位），以及水的初始温度和最终温度。 计算能量的公式是：Q = M × (最终温度 - 初始温度) × 4184
这里的M是以千克为单位的水的重量，温度以摄氏度为单位，而能量Q以焦耳为单位。 下面是一个运行示例： Enter the amount of water in kilograms : 55.5 Enter the initial temperature : 3.5 Enter the final temperature : 10.5 The energy needed is 1625484
2.10(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, initial and final temperatures are in degrees Celsius, and energy Q is measured in joules. Here is a sample run: Enter the amount of water in kilograms : 55.5 Enter the initial temperature : 3.5 Enter the final temperature : 10.5 The energy needed is 1625484
参考代码：
package chapter02; import java.util.Scanner; public class Code_10 { public static void main(String[] args) { double Joule,WaterKilo,InitTemp,FinalTemp; System.out.print("Enter the amount of water in kilograms : "); Scanner WaterInput = new Scanner(System.in); WaterKilo = WaterInput.nextDouble(); System.out.print("Enter the initial temperature : "); Scanner InitTempInput = new Scanner(System.in); InitTemp = InitTempInput.nextDouble(); System.out.print("Enter the final temperature : "); Scanner FinalTempInput = new Scanner(System.in); FinalTemp = FinalTempInput.nextDouble(); Joule = WaterKilo * (FinalTemp - InitTemp) * 4184; System.out.println("The energy needed is " + Joule); } } 结果显示： Enter the amount of water in kilograms : 55.5 Enter the initial temperature : 3.5 Enter the final temperature : 10.5 The energy needed is 1625484.0 Process finished with exit code 0