Scientific Programming II

ModSim

Unit 1 - Assignment

Problem 1

Write a program to simulate the vertical free fall of an object. Start by writing a class called Particle to represent the falling object. The properties of the Particle class will defined as below:

Properties

A time variable (double)
A constant (static) gravity variable (double, 9.8)

Methods

A default constructor which initializes the value of time to zero
A void method which takes an input for a time value and assigns the value to the time variable
A method which returns the vertical height (in double) for the assigned time value
A method which returns the vertical velocity (in double) for the assigned time value

Necessary Equations

s_y = (0.5)at²
v_y = at

In addition, write a test program to perform the following functions:

The program should ask the user for the total time of free fall in seconds
The program should ask the user for the length of each time interval in seconds
The program should compute the total number of time intervals for this simulation
The program should define a variable of type, Particle.
Using the methods defined in the Particle class, the program should compute the vertical distance and vertical velocity for each time interval.
Using the sleep method in the Thread class, the program should simulate the time delay for each time interval.
Once the program is completed, the program should print (in table format) the numerical values (up to two decimal places) for the time interval and the numerical values for the vertical distance and vertical velocity.

Test Program

import java.util.Scanner;
import java.text.DecimalFormat;
 
public class VerticalFreeFallSimulation {
    public static void main (String args[]) {
        System.out.println("Modeling a Vertical Free Fall");
        Scanner scanner = new Scanner (System.in);
        System.out.println("Total Time of Free Fall In Seconds?");
        double total_time = scanner.nextDouble();
        System.out.println("Length of Each Time Interval In Seconds?");
        double time_interval = scanner.nextDouble();
        Particle object = new Particle();
        DecimalFormat decimalformat = new DecimalFormat("0.00");
 
        System.out.println("TimeInterval" + "\t\t" + "Height" +  "\t\t\t" + "Velocity");
        System.out.println("#" + "\t\t\t" + "(m)" +  "\t\t\t" + "(m/s)" );
        for (double i = 0; i <= total_time; i += time_interval) {
            object.setTime(i);
 
            try {
                Thread.sleep((int) (time_interval * 1000));
            }
            catch (InterruptedException e) {}
                                        
            System.out.println(i + "\t\t\t" + 
                        decimalformat.format(object.verticalHeight()) + "\t\t\t" + 
                        decimalformat.format(object.verticalVelocity()));
        }
    }
}

Output

Modeling a Vertical Free Fall
Total Time of Free Fall In Seconds?
> 10
Length of Each Time Interval In Seconds?
> 0.5
Time Interval   Height      Velocity
#               (m)         (m/s)
0               0.00        0.00
1               4.90        9.80
2               19.60       19.60
3               44.10       29.40
4               78.40       39.20
5               122.50      49.00
6               176.40      58.80
7               240.10      68.60
8               313.60      78.40
9               396.90      88.20
10              490.00      98.00
11              592.90      107.80
12              705.60      117.60
13              828.10      127.40
14              960.40      137.20
15              1102.50     147.00
16              1254.40     156.80
17              1416.10     166.60
18              1587.60     176.40
19              1768.90     186.20
20              1960.00     196.00

Problem 2

Re-write Problem 1 such that the data table (as seen above) is written to an Excel file. Once the data is written to an Excel file, plot the data and observe how velocity and distance increase with time. The following program creates an Excel file called File.xls and copies all the data values to it.

Note: The Excel file will be in the same folder as your BlueJ project.

Test Program

import java.util.Scanner;
import java.text.DecimalFormat;
import java.io.FileWriter;
import java.io.IOException;
 
public class VerticalFreeFallWriteToFile {
    public static void main(String args[]) {
        System.out.println("Modeling a Vertical Free Fall");
        Scanner scanner = new Scanner (System.in);
        System.out.println("Total Time of Free Fall In Seconds?");
        double total_time = scanner.nextDouble();
        System.out.println("Length of Each Time Interval In Seconds?");
        double time_interval = scanner.nextDouble();
        Particle object = new Particle();
        DecimalFormat decimalformat = new DecimalFormat ("0.00");
 
        try {
            FileWriter filewriter = new FileWriter("File.xls"); 
            filewriter.write("Interval" + "\t\t" + "Height" +  "\t\t" + "Velocity\n");
            filewriter.write("#" + "\t\t" + "(m)" +  "\t\t" + "(m/s)" + "\n");
               
            for(double i = 0; i <= total_time; i += time_interval) {
                object.setTime(i);
                filewriter.write(i + "\t\t" + 
                            decimalformat.format(object.verticalHeight()) + "\t\t" + 
                            decimalformat.format(object.verticalVelocity())+ "\n");
            }     
            filewriter.close();
            System.out.println("End of Data Collection");
        }
        catch (IOException e) {}
    }
}

Problem 3

Re-write Problem 2 such that each of the intermediary height and velocity values are added to a LinkedList. Finally, print both lists.

Java Generics will help you here. Find a tutorial here