#!/usr/local/bin/perl
# energy.pl
# Author: Alan Levine
#>
# Calculates estimated maximum velocity for
# input height using simple energy laws
#
#<
#
require("CGI.pm");
# Load CGI.pm library to handle input and objects
use CGI qw(:standard :cgi-lib);
use CGI::Carp qw(fatalsToBrowser);
# parse form variables to array
&ReadParse;
# print return html header
print header;
if (($in{'height'} =~ /\d/) and ( $in{'height'} > 0) ) {
# set the gravity constant
if ( $in{'units'} eq "meters") {
$g = 9.8;
} else {
$g = 32.0;
}
$vel = sprintf( "%d", sqrt( 2 * $g * $in{'height'}));
print <<"end_html";
Simple Calculations
Equation Kinetic and Potential Energies
For the input height of $in{'height'} $in{'units'},
the energy equation provides an estimated maximum velocity of
$vel $in{'units'} / sec
end_html
} else {
print <<"end_html";
Simple Calculations
Equation Kinetic and Potential Energies
Sorry, but the entered height $in{'height'} $in{'units'}
is not valid. To complete the calculation, the height, must be a
number greater than 0. Please click your browser back button to try again
end_html
}
exit;