Calculating Average Velocity or Speed
Example of calculating speed and velocity
<?xml version="1.0" encoding="UTF-8"?>
<!--Tue Jan 17 2012 13:00:01 GMT-0500 (EST)-->
<XholonWorkbook>
<Notes>
Khan Academy
------------
Title: Calculating Average Velocity or Speed
Description: Example of calculating speed and velocity
Url: http://www.khanacademy.org/video/calculating-average-velocity-or-speed?playlist=Physics
InternalName: calculating-average-velocity-or-speed
YoutubeId: oRKxmXwLvUU
Keywords: Calculating, Average, Velocity, or, Speed
My Notes
--------
displacement = 5 km north
m meters
s with a right-directed arrow on top (it's a vector)
time = 1 hour
s seconds
t (a scalar)
velocity
m/s
v with a right-directed arrow on top
v = s / t
speed, rate (a scalar)
dimensional analysis
</Notes>
<script implName="lang:python:inline:"><![CDATA[
s = 5.0 * 1000.0 # m
t = 1.0 * 60.0 * 60.0 # s
v = s / t # m/s
print str(s) + "m / " + str(t) + "s = " + str(v) + "m/s"
# http://ideone.com/43jdb
# result: 5000.0m / 3600.0s = 1.38888888889m/s
]]></script>
<script implName="lang:javascript:inline:"><![CDATA[
var s = 5.0 * 1000.0; // m
var t = 1.0 * 60.0 * 60.0; // s
var v = s / t; // m/s
print(s + "m / " + t + "s = " + v + "m/s");
// paste this into your browser's address bar (exclude the // comment characters):
//javascript:(function(s,t){s=s*1000.0;t=t*60.0*60.0;var v=s/t;alert(s+"m/"+t+"s="+v+"m/s");})(5.0,1.0)
]]></script>
<_-.XholonClass>
<!-- domain objects -->
<PhysicalSystem/>
<Car/>
<!-- quantities -->
<Displacement superClass="Length"/>
<ChangeInTime superClass="Duration"/>
<AverageVelocity superClass="Velocity"/>
</_-.XholonClass>
<xholonClassDetails>
<Car>
<port name="displacement" connector="#xpointer(Displacement)"/>
<port name="changeInTime" connector="#xpointer(ChangeInTime)"/>
<port name="averageVelocity" connector="#xpointer(AverageVelocity)"/>
</Car>
</xholonClassDetails>
<PhysicalSystem>
<Car>
<Displacement>5.0 km</Displacement>
<Attribute_String roleName="direction">north</Attribute_String>
<ChangeInTime>1.0 h</ChangeInTime> <!-- 1 hour -->
<AverageVelocity>0.0 m/s</AverageVelocity> <!-- this will be calculated -->
</Car>
</PhysicalSystem>
<Carbehavior implName="lang:python:inline:"><![CDATA[
# Steps:
# (1) Select the displacement, direction, changeInTime, and averageVelocity nodes
# in that order.
# (2) Run this script by pasting it into the Car node in the Xholon GUI,
# or through a Xholon Console on the Car node.
snodes = selectedNodesKey
print snodes
s = snodes[0] # m
n = snodes[1] # "north"
t = snodes[2] # s
v = snodes[3] # m/s
v.setVal((s.val*1000.0) / (t.val*3600))
print "v = " + str(v.val) + " " + v.unit + " " + n.val_String
]]></Carbehavior>
<Carbehavior implName="lang:javascript:inline:"><![CDATA[
// TODO
//height.incVal(0.02);
//print("JavaScript wants something to do. Height:" + height + "\n");
]]></Carbehavior>
<Carbehavior implName="lang:bsh:inline:"><![CDATA[
// TODO
//height.incVal(0.02);
//System.out.print("Java/Beanshell wants something to do. Height:" + height + "\n");
]]></Carbehavior>
<Carbehavior implName="lang:jruby:inline:"><![CDATA[
# TODO
#require 'java'
#$height.incVal(0.02)
#puts "Ruby wants something to do. Height: #{$height}"
]]></Carbehavior>
<Carbehavior implName="lang:groovy:inline:"><![CDATA[
// TODO
//height.incVal(0.02);
//System.out.print("Groovy wants something to do. Height:" + height + "\n");
]]></Carbehavior>
</XholonWorkbook>