changes made with learning:

1. rename the file to car.xml because of Ejs has a character restriction, else it will not run.
2. verify the physics of rolling down a ramp
// derivation by lookang
// F + TM*g*sin(angle) -f = ma  N2L
// R*f = I*alpha  N2L circular motion
// s = R*angle  angular motion
// v = R*omega
// a = R*alpha
// therefore
// assume car = 4 wheels 2*fw and 2*rw
// F + TM*g*sin(angle) -2*Ifw/fwR*(a/fwR)- 2*Irw/rwR*(a/rwR) = TM.a
// since Ifw = 0.5*fwMass*fwR*fwR ;moment of inertia disc
// since Irw = 0.5*rwMass*rwR*rwR ;moment of inertia disc
// F + TM*g*sin(angle) = (TM+fwMass*fwR*fwR/(fwR*fwR)+rwMass*rwR*rwR/(rwR*rwR) )a
// therefore
// MI = (TM+fwMass+rwMass )
// or in general
// MI = (TM+k*TM) where k is the constant of I = k*TM*R^2
3. added slider L to control the length of ramp
4. allow the car to move beyond the range of Xinit to Lmin.
5. added angledegree
6 redesign the field to sliders, for consistent look
7 move thrust to bottom panel
8 move media player button to bottom right corner
9 autoscale true and square ==true for maximum view
10 move velocity into top panel
11 resize width = 600
12 added an axis to show the direction of down he slope as x' and y'. idea from http://www.compadre.org/osp/items/detail.cfm?ID=8242
13 made bummer y height follow the carSize for better view
14 debug the event for ODE evolution to be more precise to account for the position of the car as well for both top and bottom bummer.
zero condition
if(v>=0) return 1;                    
if(x-carSize/2>=xbumpertop) return 1;
return x+carSize/2;
action
v = Math.abs(v)*e;
15 added provision for e coefficient of restitution
24 June 2010
16 made the mass of car, mass of rear wheel and mass of front wheel variables and controllable through fixed relationship
17 added options for physics of solid ball like a marble, a shell like a football, a cylindrical disc like a coin in addition to the 4 wheel car already made for simpler experiments in lower secondary.
18 debug the event to return 0 so as to allow the simulation to not end after v =0 resting on the bottom bumper if it is placed above the lowest point, for students to explore average speeds concept as in some real life activity. read the bottom posts for help from the master of applets FKH :)
19 added new codes to _pause() only if the bottom bumper is at the lowest point
20 added graphics of football http://commons.wikimedia.org/wiki/File:Football_(soccer_ball).svg
21 resize crop into a perfect square
22 graphics of marble http://www.flickr.com/photos/cclau2003/3832161365/
23 added transparent background, crop to a perfect square using gimp http://www.gimp.org/downloads/
24 made slider to appear with the selected objects
11 July 2011
fixed bugs
mainly
// derivation by lookang
// F + TM*g*sin(angle) -f = ma    N2L
// R*f = I*alpha                N2L circular motion
// s = R*angle                angular motion
// v = R*omega
// a = R*alpha
// therefore
// assume car = 4 wheels 2*fw and 2*rw
// F + TM*g*sin(angle) -2*Ifw/fwR*(a/fwR)- 2*Irw/rwR*(a/rwR) = TM.a
// since Ifw = 0.5*fwMass*fwR*fwR ;moment of inertia disc
// since Irw = 0.5*rwMass*rwR*rwR ;moment of inertia disc
// F + TM*g*sin(angle) = (TM+fwMass*fwR*fwR/(fwR*fwR)+rwMass*rwR*rwR/(rwR*rwR) )a
// therefore
// MI = (TM+fwMass+rwMass )
// or in general
// MI = (TM+k*TM) where k is the constant of I = k*TM*R^2
fixed all the rest of the objects bug
added x graph as well
moved to the right side panel
added field and slider to all controls for finer control of values to investigate
added yellow hotspot to drag the slope up and down from http://www.compadre.org/osp/items/detail.cfm?ID=11236 Sliding Down an Inclined Plane Model written by Wolfgang Christian
check outcome of simulations runs with Sliding Down an Inclined Plane Model written by Wolfgang Christian with the box, solid ball, car
check outcome of simulations runs with Rocket Car on an Inclined Plane Model written by Wolfgang Christian, Francisco Esquembre, and Mario Belloni http://www.compadre.org/osp/items/detail.cfm?ID=8243
seems all values are similar now.
made v editable for angle = 0 case else there is no motion







done!