Chapter 2 Question 2.12, Introduction to Java Programming, Tenth Edition Y. Daniel LiangY.

(Physics: finding runway length) Given an airplane’s acceleration a and take-off speed v, you can compute the minimum runway length needed for an airplane to take off using the following formula:

length = v^2/ 2a 

Write a program that prompts the user to enter v in meters/second (m/s) and the acceleration a in meters/second squared (m/s2 ), and displays the minimum runway length.

Solution

import java.util.Scanner;

public class Exercise_02_12 {

    public static void main(String[] args) {

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

        // Prompt user to enter the airplane's acceleration a and take-off spead v.

        System.out.print("Enter speed and acceleration: ");

        double speed = input.nextDouble();

        double acceleration = input.nextDouble();

        // Compute the minimum runway length

        // needed for an airplane to take off.

        double length = Math.pow(speed, 2) / (2 * acceleration);

        // Display result

        System.out.println("The minimum runway length for this" +

                                 " airplane is " + length);

    }

}