[R] Absolut newbie questions

[JB]

I teach at a high school and should like to find out, if I can use R for my 
teaching. So I jhave installed it on my XP system and now I should like to 
solve a simple problem:

We have just measured dx and dt (d standing here for \Delta) on an inclined 
plain and received some data thet are in two lists (x_list and t_list). The 
theory says, that dx = a/2*(dt)^2 for a constant a.

I should like to fit the data against the theoretical prediction. This 
should deliver an estimate for a.

Then I should like to graph the data (as bullets) and the predicted 
function into the same graph.

Is this possible? I suspect that the answer is "yes" and that R is an 
overkill for this.

Could somebody tell me how to do these things? (I need only a few lines of 
MuPad or Maple for this; the problem is that I own a MuPad license but the 
school does not.)

TIA,
Janos Blazi