Chapter 2 Question 2.17, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

(Science: wind-chill temperature) How cold is it outside? The temperature alone is not enough to provide the answer. Other factors including wind speed, relative humidity, and sunshine play important roles in determining coldness outside. In 2001, the National Weather Service (NWS) implemented the new wind-chill temperature to measure the coldness using temperature and wind speed. The formula is 

twc = 35.74 + 0.6215ta - 35.75v^0.16 + 0.4275tav0.16 

where ta is the outside temperature measured in degrees Fahrenheit and v is the speed measured in miles per hour. twc is the wind-chill temperature. The formula cannot be used for wind speeds below 2 mph or temperatures below -58 ºF or above 41ºF. Write a program that prompts the user to enter a temperature between -58 ºF and 41ºF and a wind speed greater than or equal to 2 and displays the wind-chill temperature. Use Math.pow(a, b) to compute v^0.16

Solution

/*

(Science: wind-chill temperature) How cold is it outside? The temperature alone

is not enough to provide the answer. Other factors including wind speed, relative

humidity, and sunshine play important roles in determining coldness outside.

In 2001, the National Weather Service (NWS) implemented the new wind-chill

temperature to measure the coldness using temperature and wind speed. The

formula is:

        twc = 35.74 + 0.6215ta - 35.75v^0.16 + 0.4275tav^0.16

where ta is the outside temperature measured in degrees Fahrenheit and v is the

speed measured in miles per hour. twc is the wind-chill temperature. The formula

cannot be used for wind speeds below 2 mph or temperatures below -58 ºF or

above 41ºF.

Write a program that prompts the user to enter a temperature between -58 ºF and

41ºF and a wind speed greater than or equal to 2 and displays the wind-chill temperature.

Use Math.pow(a, b) to compute v0.16

*/

import java.util.Scanner;

public class Exercise_02_17

{

    public static void main(String[] args)

    {

        Scanner input = new Scanner(System.in);

        // Prompt the user to enter a temperature between -58F and

        // 41F and a wind speed greater than or equal to 2.

        System.out.print("Enter the temperature in Fahrenheit " +

            "between -58ºF and 41ºF: ");

        double temperature = input.nextDouble();

        System.out.print("Enter the wind speed (>= 2) in miles per hour: ");

        double speed = input.nextDouble();

        // Compute the wind chill index

        double windChill = 35.74 + 0.6215 * temperature -

        35.75 * Math.pow(speed, 0.16) +

        0.4275 * temperature * Math.pow(speed, 0.16);

        // Display result

        System.out.println("The wind chill index is " + windChill);

    }

}

OUTPUT

Enter the temperature in Fahrenheit between -58ºF and 41ºF: 20

Enter the wind speed (>= 2) in miles per hour: 4

The wind chill index is 14.21540906987616