Find the time it takes the boat to travel the given distance. A ball is thrown vertically upward with a speed of 40.0 m/s. How high does it rise? How long does it take to reach its highest point? How long does the ball take to hit the ground after it reaches its highest point? What is its velocity when it returns to the level from which it started? The center of mass moves with constant acceleration when constant forces act on the object. A gym ground. How high above this point is her center of mass at the following times? Ignore the effects Solution initial velocity, u = + 40 m/s a = - 9.8 m/s^2 (a) it will rise until its velocity becomes zero. hence final velocity, v = 0 Applying, v^2 - u^2 = 2 a h 0^2 - 40^2 = 2(-9.8)(h) h = 81.63 m (B) v = u + at 0 = 40 - 9.8 t t = 4.08 sec (C) now for motion from highest point to ground, initial velocity, v (velocity at highets point) = 0 displacement, y = - 81.63 m a = - 9.8 m/s^2 applying, y = u t + a t^2 /2 - 81.63 = 0 - 9.8 t^2 / 2 t = 4.08 s (D) applying v = u + at v = 0 + (-9.8)(4.08) v = - 40 m/s (minus sign indicates that direction is downwards).

1. For this lab you will complete the class MyArrayList by implementing the MyList interface
provided. The implementation you write must use an array of Object, declared like this:
private Object[] theList;
To successfully implement the interface you must provide a non-abstract version of all the
methods in the interface.
Add functionality that ensures only one type of reference can be added to your
list. In other words, make your list "type-safe'.
Create an overloaded constructor in MyArrayList public MyArrayList( Object type). The
constructor parameter will
be used to set the type of reference to be added to the list. Set up a private filed of the same type
as the parameter. You will also instantiate your Object[] in this constructor. Do not change the
default constructor.
In public boolean add(Object toAdd) you will first check the toAdd parameter to ensure it is the
same as
the type you set in the overloaded constructor. If it is then go ahead and add the reference to
your list. If
not then return false and display an error message indicating the method parameter was rejected
due to
incompatible type.
To check the "toAdd" parameter you will have to first have to get the type of class it is (HINT:
look at
Object methods). Next, you will need to check its type against the type you established in the
overloaded constructor (HINT: look at the Class methods).
Finally, provide a driver class that will:
1) create the an instance of MyList and then add references to it. Be sure to try incompatible
types.
2) Check to see if the list is empty.
3) Display the contents of the list.
4) Display the size of the list.
5) Display the first element in the list.

2. 6) Remove the first element in the list.
7) Display the list one final time.
Modify the classes bellow to match the information above:
/**
* MyArrayList - an imlementation of an array list based on a Java array.
*
* @author Colleen
* @version 2013.11.15
*/
public class MyArrayList
{
private Object[] theList; // array of objects
/**
* Constructor - start with an empty array
*/
public MyArrayList()
{
theList = new Object[0];
}
/**
* Adds a new element at the end of the list.
* @param the object to add
* @return true if element successfully added, false if parameter is null
*/
public boolean add(Object toAdd){
return false;
}
/**
* Gets the object at the specified index.
* @param index value of object to get
* @return object at that index
*/
public Object get(int index){

3. return null;
}
/**
* Removes specified object from list.
* @param index value of object to remove
* @return the object removed
*/
public Object remove(int index) {
return null;
}
/**
* Returns size of the list
* @return number of elements in the list
*/
public int size(){
return 0;
}
/**
* @return true if the list has no elements, false otherwise
*/
public boolean isEmpty(){
return false;
}
}
------------------------------------
/**
* Write a description of interface List here.
*
* @author (your name)

4. * @version (a version number or a date)
*/
public interface MyList
{
/**
* Adds a new element at the end of the list.
* @param the object to add
* @return true if element successfully added, otherwise false
*/
boolean add(Object toAdd);
/**
* Gets the object at the specified index.
* @param index value of object to get
* @return object at that index
*/
Object get(int index);
/**
* Removes specified object from list.
* @param index value of object to remove
* @return the object removed
*/
Object remove(int index);
/**
* Returns size of the list
* @return number of elements in the list
*/
int size();
/**
* @return true if the list has no elements, false otherwise
*/
boolean isEmpty();

5. }
Solution
/**
* Write a description of interface List here.
*
* @author (your name)
* @version (a version number or a date)
*/
public interface MyList {
/**
* Adds a new element at the end of the list.
*
* @param the
* object to add
* @return true if element successfully added, otherwise false
*/
boolean add(Object toAdd);
/**
* Gets the object at the specified index.
*
* @param index
* value of object to get
* @return object at that index
*/
Object get(int index);
/**
* Removes specified object from list.
*
* @param index
* value of object to remove
* @return the object removed
*/
Object remove(int index);
/**

6. * Returns size of the list
*
* @return number of elements in the list
*/
int size();
/**
* @return true if the list has no elements, false otherwise
*/
boolean isEmpty();
}
-----------------------------------------
import java.util.Arrays;
/**
* MyArrayList - an imlementation of an array list based on a Java array.
*
* @author Colleen
* @version 2013.11.15
*/
public class MyArrayList implements MyList {
private Object[] theList; // array of objects
Class c; //type of reference
int size = 0; //size of array
/**
* Constructor - start with an empty array
*/
public MyArrayList() {
theList = new Object[0];
}
public MyArrayList(Object type) {
c = type.getClass(); //initialize the array type
theList = new Object[1]; //initialize the array with size 1
theList[0] = type; //initialize the element in the array
size = size + 1;
}
/**
* Adds a new element at the end of the list.

7. *
* @param the
* object to add
* @return true if element successfully added, false if parameter is null
*/
public boolean add(Object toAdd) {
if (this.c != null && !(toAdd.getClass().equals(this.c))) {
System.out.println("Incompatible Argument type " + toAdd);
return false;
} else if (this.c == null) {
this.c = toAdd.getClass();
theList = new Object[1];
} else if (toAdd.getClass().equals(this.c)) {
theList = Arrays.copyOf(theList, this.size + 1);
}
this.size = this.size + 1;
theList[this.size - 1] = toAdd;
return true;
}
/**
* Gets the object at the specified index.
*
* @param index
* value of object to get
* @return object at that index
*/
public Object get(int index) {
if (!(this.isEmpty())) {
return theList[index];
} else
return null;
}
/**
* Removes specified object from list.
*
* @param index

8. * value of object to remove
* @return the object removed
*/
public Object remove(int index) {
Object item = theList[index];
for (int i = index; i < this.size - 1; i++) {
theList[i] = theList[i + 1];
}
this.size = this.size - 1;
theList = Arrays.copyOf(theList, this.size);
System.out.println("Element removed successfully.");
return item;
}
/**
* Returns size of the list
*
* @return number of elements in the list
*/
public int size() {
return size;
}
/**
* @return true if the list has no elements, false otherwise
*/
public boolean isEmpty() {
if (size == 0) {
return true;
}
return false;
}
}
----------------------------------------------------
public class TestClass {
public static void main(String[] args) {
MyList obj = new MyArrayList();
obj.add(1);

9. obj.add(5);
obj.add(7);
obj.add("test");
obj.add(9);
obj.add(4);
System.out.println("Is this List empty: "+obj.isEmpty());
System.out.println("contents of the list :");
for (int i = 0; i < obj.size(); i++) {
System.out.println(obj.get(i));
}
System.out.println("Size of the List: " + obj.size());
System.out.println("first element in the list: "+obj.get(0));
obj.remove(0);
obj.remove(3);
System.out.println("contents of the list :");
for (int i = 0; i < obj.size(); i++) {
System.out.println(obj.get(i));
}
}
}