@Preben Alsholm 

Thanks a lot! I also understand it a lot better now, though I could still ask many questions ;)

Two small questions I want to ask for now:

- how did you decide epsilon?

- how do you decide on the range for which to do the fsolve, which was 0..1,0..7 now? Or you just try?

Kind regards,

Elise

@Preben Alsholm 

First of all thanks for your answer. Yesterday I didn't have time to look at it, but today I was very happy to see that you found a better way to solve the problem.

I really believed I had found the answer but unfortunately that was too easy.. ;)

I do believe that you are right and am trying to apply your procedure to my particular problem and even though I think I have come quite far, my mathematics/Maple knowledge is not enough to fully comprehend what I am doing and which final steps I should take to come to the answer. 

Especially after doing this:

px := proc (T, v0) p(args)[1] end proc;

py := proc (T, v0) p(args)[2] end proc;

I again use the fsolve as in your sheet, is that right? But I receive no solution, should I do something else?

sol := fsolve([px, py], [0 .. 1, 0 .. 7]);
fsolve([px, py], [0 .. 1, 0 .. 7])

Thanks!

I found the solution! One major mistake was in the way I calculated the frontal area of the ball, I used the formula for circumference... Also I kept the angle at 20 degrees.

Furthermore in the end I didn't use the fsolve to solve the system as you described it, because the way in the sheet you can see below gave more believable results.

Assignment_question_1_pging_3.mw

Anyway, thanks a lot!

Elise

@Preben Alsholm  

Thank you very much for your reply. 

It is actually had the signum added to the vertical airdrag, I only forgot that I removed it temporarily to check whether things would work better without it, but I've put it back now.

For the rest, yes I think that the angle is wrong indeed and I've changed it to 20 degrees for now. (We had to measure it from a SolidWorks model and I think I did a wrong measurement). This looks a lot better already for now all the RootOf parts are removed. I also divided the distance by 1.5, although that it is not correct for the assignment, but I'll use it for now.

I am now trying to solve the system in the way you mentioned (thanks for that!) and indeed I get some solution, but the numbers are far too large. So I think I still have some mistakes, but it looks a lot better already.

Thanks!

And no it should not be distance + s0x, the real distance travelled is distance - s0x. I hope I covered that by choosing s0x this way and sy as 2.5