The finished program is given below.
The complete program can be copied and pasted into an editor, and run in the usual way.
import java.util.Scanner;
// User picks ending value for time, t.
// The program calculates and prints
// the distance the brick has fallen for each t.
//
public class FallingBrick
{
public static void main (String[] args )
{
final double G = 9.80665; // constant of gravitational acceleration
int t, limit; // time in seconds; ending value of time
double distance; // the distance the brick has fallen
Scanner scan = new Scanner( System.in );
System.out.print( "Enter limit value: " );
limit = scan.nextInt();
// Print a table heading
System.out.println( "seconds\tDistance" ); // '\t' is tab
System.out.println( "-------\t--------" );
t = 0 ;
while ( t <= limit )
{
distance = (G * t * t)/2 ;
System.out.println( t + "\t" + distance );
t = t + 1 ;
}
}
}
You could also write
distance = 0.5*G*t*t;
What were the two traps in translating the formula?
If you translated it as
(1/2)*G*t*t,
you fell into the first trap.
(1/2) asks for integer division of 1 by 2, resulting in zero.
If you translated the formula as
1/2*G*t*t,
you fell into the second trap.
To the compiler,
this looks like the first wrong formula
because / has equal precedence to *
and so 1/2 is computed first, resulting in zero.
A third problem is computing the square.
Do it as t
multiplied by t.
Now say that you want the table to show time increasing in steps of 0.1 seconds. Modify the program so that it does this with maximum accuracy. The user enters the limit in seconds.