Getting Hot in Physics

Well, to say that today did not go as expected would be the understatement of the school year!

My Principles of Technology class has been working on building model rockets as part of a unit that was analyzing the physics concepts of impulse, velocity, and acceleration, the chemistry concept of balanced chemical equations/reactions, and the engineering concept of technical drawing/documentation.

Today was the day that we launched. We had 6 small single-stage rockets to launch in addition to 2 small two-stage rockets.

Each single-stage rocket was loaded with a single A-rated motor which would carry it to a total altitude of approximately 250 feet. Each two-stage rocket was loaded with two C-rated motors which would carry it to a total altitude of approximately 1,800 feet!

Before going outside, we verified the weather conditions, which showed winds from the west at 7 MPH with guests to 11 MPH. The humidity was 41% and dropping. We decided to launch from the west side of the property with the idea that the winds would carry the rockets onto the soccer fields which had recently been watered.

Rocket Launch Site
Rocket Launch Site

Our first launch of the morning performed as expected and came down next to the roadway by the launch site.

Our second launch of the day did not perform as well. The first stage of the rocket fired as designed and carried the rocket to around 900 feet. Unfortunately, the first stage did not properly separate as designed and the rocket began to tumble back to the ground.

After a few seconds, the second stage ignited which sent the rocket flying on the path it was pointing at, which was toward the ground west of our launch location and it ignited the cardboard frame of the first stage which was now in a free-fall into the field to the west of the launch location.

Rocket Crash Site
Rocket Crash Site

The rocket came down about 100 yards west of the launch pad and the first stage landed about 30 yards to the east of the crash site. Unfortunately, since the first stage was on fire when it landed and it landed in a field of 1 meter tall grass/hay, the field was quickly engulfed in fire.

Rocket Burn Area
Rocket Burn Area

Ultimately, the crash resulted in the burning of approximately 1 acre of grassland which is fortunately owned by the school.

Because of the quick response of the Ferris Fire Department, the fire was quickly contained and everyone was safe with the only loss being the grassland, the rocket launcher, and the rocket launch stand.

Burned Field
Burned Field
Burned Launcher in Grass
Burned Launcher in Grass
Burned Launcher Inside
Burned Launcher Inside

Arrays with Keyboard Interactivity

Today, we discussed how to create an array with keyboard interactivity. The user will be asked to enter how many numbers they will be entering and then they will be asked to enter numbers separated by a space.

//Program Name: Arrays with Keyboard Input
//Programmer Name: Eric Evans, M.Ed.
//Programmer Organization: Ferris High School
//Program Date: Spring 2017

import java.util.*;
import java.lang.*;
import java.io.*;

public class arrayKeys {
  public static void main(String args[]){
    Scanner count = new Scanner(System.in);
    System.out.print("How Many Numbers Do You Want to Enter?: ");
    int arraySize = count.nextInt();
    int myArray[] = new int[arraySize];
    Scanner nums = new Scanner(System.in);
    System.out.println("Enter Your " + arraySize + " numbers each separated by a space and press enter when done.");
    for(int counter = 0; counter < arraySize; counter++){
      myArray[counter] = nums.nextInt();
    }
  System.out.println(Arrays.toString(myArray));
  }
}

Following the header information (lines 1 through 4) and the imports (lines 6 through 8), we get to the actual application code.

On line 12, we declare a scanner object named “count” which will receive input from the keyboard.

On line 13, we ask the user to enter the number of items they will be entering. Lines 14 assigns the value that is entered as an integer variable named “arraySize”.

Line 15 creates an empty array named “myArray” which is initialized as the size of the “arraySize” variable declared on line 14.

Line 16 declares a second scanner object named “nums” which will receive the integers to the recorded from the keyboard.

On line 17, we ask the user to enter the integers they want recorded separated by a space.

Line 18 opens a for loop. The loop initialization creates an integer variable named “counter” with the value of 0. The loop condition is to run while the variable “counter” is less than the variable “arraySize”, which was declared on line 14. Each pass through the loop increments the value of the variable “counter” by 1.

Each pass through the loop executes line 19, which assigns the next integer in the sequence of numbers from the “nums” scanner to “myArray” in the index (position) declared by the “counter” variable.

Finally, on line 21, we output the contents of “myArray” as a string.

Coding Bat – rotateLeft3

This exercise requires that the program look at an array with 3 integers and shift their positions one index to the left (down) and place first integer (index 0) at the end.

Here is the code that you start with:

public int[] rotateLeft3(int[] nums) {

}

As you can see, we start with an empty integer array named “nums”.

public int[] rotateLeft3(int[] nums) {
  int[] rotatedArray = new int[]{nums[1],nums[2],nums[0]};
  return rotatedArray;
}

 

This solution creates a new integer array named “rotatedArray” and assigns it the values of each index from the original array. (Line 2)

We return the new array on line 3 to solve the problem.

Coding Bat – posNeg

This exercise requires that the program look at two given integers and a boolean. If the Boolean is TRUE AND both integers are negative, then TRUE is returned. If the Boolean is FALSE only 1 integer can be negative for to return TRUE.

Here is the code that you start with:

public boolean posNeg(int a, int b, boolean negative) {

}

As you can see, we start with 2 integer variables named “a” and “b” and a boolean named “negative”.

public boolean posNeg(int a, int b, boolean negative) {
  if (negative){
    if (a < 0 && b < 0){
      return true;
    } else {
      return false;
    } 
  } else if ((a < 0 && b > 0) || (a > 0 && b < 0)) {
    return true;
  } else {
    return false;
  }
}

This solution utilizes a nested if/then structure. Starting on line 2, we say IF the Boolean negative is TRUE, then proceed to line 3. If it is FALSE, we would jump to line 8.

On line 3, we now check to see if both “a” AND “b” are negative (less than 0). If they are, TRUE is returned (line 4). If they are not, FALSE is returned (lines 5-7).

Line 8 is executed if the Boolean on line 3 is FALSE. Line 8 looks to see if “a” is negative and “b” is positive OR “a” is positive and “b” is negative. If either case is TRUE, then TRUE is returned (line 9). If neither statement on line 8 is TRUE, then FALSE is returned (lines 10-12).

Coding Bat presents the following as their solution:

public boolean posNeg(int a, int b, boolean negative) {
  if (negative) {
    return (a < 0 && b < 0);
  }
  else {
    return ((a < 0 && b > 0) || (a > 0 && b < 0));
  }
}

In this solution, line 2 is identical to our line 2. However, their line 3 is shorter version of our lines (3-7). If both “a” AND “b” are not negative, then a FALSE is returned, otherwise a TRUE is returned.

Their lines 5-7 are our lines 8-12 and work the same way.

Robotic Systems Classifications Exam

We have spent the past 2 weeks covering 5 different classification systems of robotic and automated systems.

We have covered degrees of freedom, drive technology, kinematic structure, motion characteristics, and workspace geometry.

Robotic Classification Systems Notes

At the conclusion of this unit, students were given a review guide and an exam.

Robotics Classifications Exam

Robotics Classifications Exam Key

The results will be posted following the administration of the exam.

Coding Bat – Arrays Cluster 1

Today, while I was attending meetings, I assigned my students to complete 4 Coding Bat logic exercises.

CODING BAT – COMMONEND

This exercise requires that the program return TRUE if the first integers or last integers of two given arrays are the same, otherwise, FALSE will be returned.

Here is the code that you start with:

public boolean commonEnd(int[] a, int[] b) {

}

We start with two integer arrays named “a” and “b”.

public boolean commonEnd(int[] a, int[] b) {
  int arrayALength = a.length;
  int arrayBLength = b.length;
  int lastA = a[arrayALength - 1];
  int lastB = b[arrayBLength - 1];
  int firstA = a[0];
  int firstB = b[0];
  if(firstA == firstB || lastA == lastB){
    return true;
  }
  return false;
}

The solution above starts by calculating the length of each array (lines 2 and 3). Remember, whenever you are asked to do anything with the “end” or “last” items, you will almost always need to calculate the length.

On lines 4 & 5, we are establishing variables to hold the last index of each array and lines 6 & 7 are holding the first index of each array.

Finally, lines 8 through 10 are a conditional statement comparing the first indices of each array and the last indices of each array. If either of them are equal, a TRUE is returned. However, if neither is TRUE, then FALSE is returned.

CODING BAT – MAKELAST

This exercise requires that the program calculate the length of a given array and create a new array that is double that length populated with zeros with the exception of the last index. The last index is to populated with the last index of the first array.

Here is the code that you start with:

public int[] makeLast(int[] nums) {

}

We start with a single integer variable named “nums”.

public int[] makeLast(int[] nums) {
 int arrayLength = nums.length;
 int arrayFinalLength = arrayLength * 2;
 int arrayLast = nums[arrayLength - 1];
 int[] num = new int[arrayFinalLength];
 num[arrayLength - 1] = arrayLast;
 return num;
}

As always, since we are asked to do some operation with the “last” or “end”, we must calculate the length of the array. This is done on line 2.

On line 3, we created a variable to hold the length of the new array, which is double the length of the original array.

Line 4 is where we capture the last index of the original array.

On line 5, we create a new integer array named “num” which has a size assigned by the variable that was created on line 3.

On line 6, we replace the last index of the new array with the value of the variable created on line 4.

Finally, on line 7, we return the new array.

CODING BAT – MAKEPI

This exercise requires that the program return the first 3 digits of PI in an array.

Here is the code that you start with:

public int[] makePi() {

}

We start with just the basic class declaration and no variables.

public int[] makePi() {
  int pi[] = {3,1,4};
  return pi;
}

The solution above starts by creating a new integer array named “pi” which is assigned the integers of 3, 1, and 4 on line 2.

On line 3, the array is returned.

Many students struggle to make this problem more challenging than it needs to be. Some try to take the Math.PI constant and populate the array one index at a time. However, this is not necessary and is not outlined as a requirement in the problem.

 

Coding Bat – Cluster 3

Today, while wrapping-up our conversation over arrays, we worked a series of 3 different basic array problems from Coding Bat.

CODING BAT – CIGARPARTY

This exercise requires that the program return true if number of cigars is between 40 and 60 on weekdays and at least 40 on weekends.

Here is the code that you start with:

public boolean cigarParty(int cigars, boolean isWeekend) {

}

We start with a single integer named cigars and a boolean named isWeekend.

public boolean cigarParty(int cigars, boolean isWeekend) {
  if (isWeekend){
    if (cigars >= 40){
      return true;
    }else{
      return false;
    }
  }else{
    if (cigars >=40 && cigars <=60){
      return true;
    }else{
      return false;
    }
  }
}

The solution above starts with a Boolean conditional to check to see if it is a weekend (line 2). If it is not a weekend, then the code jumps to line 8. However, if it is a weekend, the code continues on to line 3.

Line 3 looks to see if the number of cigars is at least 40. If it is, then a TRUE is returned, otherwise a FALSE is returned.

If it is not a weekend, the code jumped to line 8. Starting at line 9, we look to see if the number of cigars is between 40 and 60. If it is, then a TRUE is returned, otherwise a FALSE is returned.

CODING BAT – DATEFASHION

This exercise requires that the program calculate the probability of you and your date getting a table at a restaurant based upon how stylish the clothes you and your date are wearing.

Here is the code that you start with:

public int dateFashion(int you, int date) {

}

We start with two integer variables named “you” and “date”.

public int dateFashion(int you, int date) {
  if (you <= 2 || date <= 2){
    return 0;
  }else if(you >= 8 || date >= 8){
    return 2;
  }else{
    return 1;
  }
}

Our first Boolean conditional statement is located on line 2 where we check to see if either “you” or your “date” are wearing anything that is a 2 or lower. If so, then a “0” is returned.

If the first Boolean is FALSE, then we move to the second Boolean conditional statement on line 4 which is checking to see if either “you” or your “date” are wearing anything that is an 8 or higher. If so, then a “2” is returned.

Finally, if second Boolean is also FALSE, then we automatically return a “1” as the numbers for “you” and your “date” are between 2 and 8 exclusive of those numbers.

CODING BAT – SQUIRRELPLAY

This exercise requires that the program state whether the squirrels will come out to play. The squirrels like to play when the temperature is between 60 and 90 degrees, unless it is summer. In the summer, they will stay out up to 100 degrees.

Here is the code that you start with:

public boolean squirrelPlay(int temp, boolean isSummer) {

}

We start with one integer variable named “temp” and a boolean variable named isSummer.

public boolean squirrelPlay(int temp, boolean isSummer) {
  if (isSummer){
    if (temp >= 60 && temp <= 100){
      return true;
    }else{
      return false;
    }
  }else{
    if (temp >= 60 && temp <= 90){
      return true;
    }else{
      return false;
    }
  }
}

The solution above starts with a Boolean conditional to check to see if it is summer (line 2). If it is not summer, then the code jumps to line 8. However, if it is summer, the code continues on to line 3.

Line 3 looks to see if the temperature is between 60 and 100 degrees. If it is, then a TRUE is returned, otherwise a FALSE is returned.

If it is not summer, the code jumped to line 8. Starting at line 9, we look to see if the temperature is between 60 and 90 degrees. If it is, then a TRUE is returned, otherwise a FALSE is returned.

CODING BAT – ALARMCLOCK

This exercise requires that the program return what time the alarm clock with sound with the given criteria:

  • If it is a vacation weekday, then the alarm will sound at 10:00.
  • If it is a vacation weekend, then the alarm is off.
  • If it a weekday, then the alarm will sound at 7:00.
  • If it is a weekend, then the alarm will sound at 10:00.

Here is the code that you start with:

public String alarmClock(int day, boolean vacation) {

}

As you can see, we have an integer variable named “day” and a Boolean variable named “vacation”.

public String alarmClock(int day, boolean vacation) {
  if (vacation){
    if (day >= 1 && day <= 5){
      return "10:00";
    }else{
      return "off";
    }
  }else{
    if (day >= 1 && day <= 5){
      return "7:00";
    }else{
      return "10:00";
    }
  }
}

Staring at line 2, we have a Boolean conditional which looks to see if it is a vacation. If it is not a vacation day, then the code skips to line 8. If it is a vacation day, then we proceed to line 3 where we look to see if it is a weekday (days 1 through 5). If it is a weekday, the application will return the string “10:00” otherwise, the application returns the string “off”.

Looking at line 9, we are processing for a non-vacation day and look to see if it is a weekday (days 1 through 5) and then return the string “7:00” if it is a weekday. If it is a weekend, then we return the string “10:00”.

Coding Bat – firstLast6

This exercise requires that the program analyze an array of integers and return TRUE if either the first or last integer is a 6. The array is guaranteed to have a minimum length of 1.

Here is the code that you start with:

public boolean firstLast6(int[] nums) {

}

As you can see, we have a single integer array named nums.

public boolean firstLast6(int[] nums) {
 int first = nums[0];
 int last = nums[nums.length-1];
 if (first == 6 || last == 6){
   return true;
 }
 return false;
}

This solution utilizes a conditional if with the Boolean OR to solve the problem.

We start my declaring an integer variable named “first” to retrieve the value of index 0 (line 2).

We then declare an integer variable named “last” to retrieve the value of the last letter (Line 3)

As was the case when working with strings, to retrieve the last index of the array, we must first calculate its length and then subtract 1 from the total length. This will give us the value of the last index of the array.

Lines 4 through 6 are the conditional Boolean OR looking to see if either the first or last number are 6. If the Boolean is TRUE, then TRUE is returned.

Coding Bat – sameFirstLast

This exercise requires that the program analyze an array of integers and return TRUE if the array has a length greater than 1 and the first index is the same as the last index.

Here is the code that you start with:

public boolean sameFirstLast(int[] nums) {

}

As you can see, we have a single integer array named nums.

public boolean sameFirstLast(int[] nums) {
 if (nums.length >= 1){
   int first = nums[0];
   int last = nums[nums.length-1];
   if (first == last){
     return true;
   }
   return false;
   }
 return false;
}

We start on line 2 checking to see if the array has a minimum length of 1. If is does not, we skip to line 10 and return FALSE. If the Boolean on line 2 is true, we proceed to line 3.

We then declare an integer variable named “first” to retrieve the value of index 0 (line 3).

We then declare an integer variable named “last” to retrieve the value of the last letter (Line 4)

As was the case when working with strings, to retrieve the last index of the array, we must first calculate its length and then subtract 1 from the total length. This will give us the value of the last index of the array.

Lines 5 through 7 are the conditional Boolean looking to see if the first and last index are the same value. If the Boolean is TRUE, then TRUE is returned.

Starting with Arrays

Today, we started working with basic arrays in class. Before we got into them, we compared them to stacks. We discussed some of the applicable uses of stacks and how they are ideal for a queue where records must remain in the order they were received.

After the discussion reviewing stacks, I then compared them to a basic array. We discussed that while we can select and manipulate any index within an array, the array is a finite size. We discussed advantages and disadvantages of the two data structures. We then moved into practicing with some code.

//Program Name: Starting with Arrays
//Programmer Name: Eric Evans, M.Ed.
//Programmer Organization: Ferris High School
//Program Date: Spring 2017

import java.util.*;

public class arrays1 {
 public static void main(String args[]){
 int myFirstArray[] = {100, 25, 63, 3, 12, 50, 85};
 
 //Print the Array
 for(int i=0; i<myFirstArray.length; i++){
   System.out.print(myFirstArray[i] + " ");
 }
 
 //Alternate Way to Print the Array
 System.out.println("");
 for(int everyElement: myFirstArray){
   System.out.print(everyElement + " ");
 }
 
 //Adding the Items in the Array
 System.out.println("");
 int total = 0;
 for(int i=0; i<myFirstArray.length; i++){
   total += myFirstArray[i];
 }
 System.out.println("Total is " + total);
 
 //Sorting the Items in the Array
 Arrays.sort(myFirstArray);
 for(int everyElement: myFirstArray){
   System.out.print(everyElement + " ");
 }
 
 //Locate the Largest Item in the Array
 System.out.println("");
 int max = myFirstArray[0];
   for (int i=1;i<myFirstArray.length; i++){
     if (myFirstArray[i] > max)max = myFirstArray[i];
   }
 System.out.println("Max is " + max);
 }
}

We started the notes by creating the array (line 10). We also discussed the difference between:

int[] myFirstArray = {100, 25, 63, 3, 12, 50, 85};

and

int myFirstArray[] = {100, 25, 63, 3, 12, 50, 85};

The first method is the preferred method for JAVA. The second method was added to the syntax to accommodate programmers who had worked in C++.

Lines 13 through 15 focus on how to display the contents of the array using the for loop..

On line 13, we have a for loop that will start iterating (counting) at 0 using the variable “i” to do the counting. The loop will continue to run until “i” is no longer less than the length of the array. After the loop is successfully run, “i” is incremented by 1.

On line 14, we have what will be executed in each iteration of the loop. The instruction says to print myFirstArray[i].

Remember, the first time through the loop, i = 0. So, line 14 will print index 0 of myFirstArray, which is the first record in the array. The second time through the loop, i = 1. At this point, it will print index 1 of myFirstArray, which is the second record in the array. This process will continue until the end of the array is reached.

Lines 19 through 21 focus on how to display the contents of the array using the foreach loop.

On line 19, we start with a for loop but the conditions are completely different. We declare an integer variable named “everyElement” and set it to have the value received from myFirstArray.

Line 20 prints the value of the variable “everyElement”.

The foreach loop runs through until each and every record has been touched.

Lines 25 through 29 discuss how to calculate the sum of the array.

On line 25, we declare an integer variable named “total” with an initial value of 0.

On line 26, we create a for loop identical to the one used on line 13. This will allow us to traverse the entire array.

On line 27, we take the variable “total” and add the currently selected index to it.

  • On the first pass, we have 0 + 100 = 100
  • On the second pass, we have 100 + 25 = 125
  • On the third pass, we have 125 + 63 = 188
  • On the fourth pass, we have 188 + 3 = 191
  • On the fifth pass, we have 191 + 12 = 203
  • On the sixth pass, we have 203 + 50 = 253
  • On the seventh and final pass, we have 253 + 85 = 338

This section could have been solved also using a foreach loop as outlined below:

int total = 0;
for(int everyElement: myFirstArray){
    total += everyElement;
}
System.out.println("Total is " + total);

Lines 32 through 35 cover how to sort an array.

Line 32 uses the sort function of the Arrays sub-library of the java.util library to sort the array. The sort function was imported on line 6.

Line 33 is a foreach loop (identical to the one seen on line 19.

Line 34 prints the array as it did on line 20.

This section could have been solved also using a traditional for loop as outlined below:

Arrays.sort(myFirstArray);
for(int i=0; i<myFirstArray.length; i++){
  System.out.print(myFirstArray[i] + " ");
}

Finally, in lines 39 to 43, we analyze how to locate the largest item in the array.

We start by declaring an integer variable named “max” and assign it the value of index 0 of the array. Since the array was just sorted on line 32, index 0 is now 3. As such, the variable “max” now has a value of 3.

Line 40 uses a slightly modified for loop as it starts iterating at 1 and not 0 as we did on line 13 and on line 26.

Line 41 uses a conditional if statement to check if the current iterated index of the array is greater than the variable “max”. If the statement is TRUE, the variable “max” is assigned the value of the iterated index. If is it FALSE, the variable “max” remains with its currently assigned value. This process repeats until the entire array is traversed.

As has been the case through all of this, you could use a foreach loop on this section of the problem as well. Here is what that code would look like with a foreach loop:

int max = myFirstArray[0];
  for (int everyElement: myFirstArray){
   if (everyElement > max)max = everyElement;
  }
System.out.println("Max is " + max);

Here is the code using traditional for loops:

//Program Name: Starting with Arrays
//Programmer Name: Eric Evans, M.Ed.
//Programmer Organization: Ferris High School
//Program Date: Spring 2017

import java.util.*;

public class arrays1 {
 public static void main(String args[]){
 int myFirstArray[] = {100, 25, 63, 3, 12, 50, 85};
 
 //Print the Array with for Loop
 for(int i=0; i<myFirstArray.length; i++){
   System.out.print(myFirstArray[i] + " ");
 }
 
 //Print the Array with foreach Loop
 System.out.println("");
 for(int everyElement: myFirstArray){
   System.out.print(everyElement + " ");
 }
 
 //Adding the Items in the Array
 System.out.println("");
 int total = 0;
 for(int i=0; i<myFirstArray.length; i++){
   total += myFirstArray[i];
 }
 System.out.println("Total is " + total);
 
 //Sorting the Items in the Array
 Arrays.sort(myFirstArray);
 for(int i=0; i<myFirstArray.length; i++){
   System.out.print(myFirstArray[i] + " ");
 }
 
 //Locate the Largest Item in the Array
 System.out.println("");
 int max = myFirstArray[0];
   for (int i=1;i<myFirstArray.length; i++){
     if (myFirstArray[i] > max)max = myFirstArray[i];
   }
 System.out.println("Max is " + max);
 }
}

Here is the code use foreach loops:

//Program Name: Starting with Arrays
//Programmer Name: Eric Evans, M.Ed.
//Programmer Organization: Ferris High School
//Program Date: Spring 2017

import java.util.*;

public class arrays1 {
 public static void main(String args[]){
 int myFirstArray[] = {100, 25, 63, 3, 12, 50, 85};
 
 //Print the Array with for Loop
 for(int i=0; i<myFirstArray.length; i++){
   System.out.print(myFirstArray[i] + " ");
 }
 
 //Print the Array with foreach Loop
 System.out.println("");
 for(int everyElement: myFirstArray){
   System.out.print(everyElement + " ");
 }
 
 //Adding the Items in the Array
 System.out.println("");
 int total = 0;
 for(int everyElement: myFirstArray){
   total += everyElement;
 }
 System.out.println("Total is " + total);
 
 //Sorting the Items in the Array
 Arrays.sort(myFirstArray);
 for(int everyElement: myFirstArray){
   System.out.print(everyElement + " ");
 }
 
 //Locate the Largest Item in the Array
 System.out.println("");
 int max = myFirstArray[0];
   for (int everyElement: myFirstArray){
    if (everyElement > max)max = everyElement;
   }
 System.out.println("Max is " + max);
 }
}

As you can see, both result in the same number of lines of code. It would ultimately be programmer’s preference and customer request for which loop structure would be used.