-------- Forwarded Message --------

Subject:	Dr Geo: A point needs to be animated over a preexisting object?
Date:	Mon, 21 Sep 2015 20:09:29 -0500
From:	Offray Vladimir Luna C��rdenas <offray.luna@mutabit.com>
To:	Any question about pharo is welcome <pharo-users@lists.pharo.org>

Hi,

Some of my students are exploring modeling as a tool to understand physical phenomena. In particular they're working on uniform movement. The idea is to take data from a lab experiment on uniform movement and plot it on a geometrical program and then use animation to reproduce the lab movement inside the plotting to see if they can get the analitycal expression which models the movement. The bridge between experimental data and the analytical expression is animation as a way to validate, reconstruct models. We're considering geogebra and DrGeo for this. I'm more familiar with smalltalk that with javascript, but the question we're facing is how to animate a point following a vector direction but going beyond it.

Considering the following figure:



So the idea is that A, B, C and D are points in a position versus time graph taken from the real lab experiment. "p" is a point which will follow the trajectory of the vector "u", which has the same direction of the segment that goes from A to B (it can be even overlapped) and is animated describing the red trajectory going for p to p' (which has the same x value of D, but a different y value). A way to do it will be put and invisible line that passing from A to B (and beyond) and make the point "p" move on it, but we're wondering if there is a way to just give vector direction and magnitude and make the point move, without creating an explicit line before.

Seems that nor geogebra or DrGeo can deal with animating a free object following a (vectorial described) trajectory.
Is this possible?

Cheers,

Offray