Odesolve and if (a task about skydiver)

[ValeryOchkov]

See please the picture and the file (Mathcad Prime 2) in attach.

What I need!?

1) Your comments and suggestions.

2) More real input data

3) And, of course, that you praise me

[AlanStevens]

Valery Ochkov wrote:

See please the picture and the file (Mathcad Prime 2) in attach.

What I need!?

1) Your comments and suggestions.

2) More real input data

3) And, of course, that you praise me

1. I suggest it's difficult to read and understand the ode in the form you've used. I think it's easier in the form I've used in the attached. Also, if you are interested in velocity as well as displacement then the state space form is better (more accurate velocity - see velocity graph).

2. I don't have any real data.

3. You are brilliant!

Alan

[ValeryOchkov]

Thanks Alan!

I think a good variant is

[AlanStevens · Accepted solution]

Valery Ochkov wrote:

Thanks Alan!

I think a good variant is

Yes, this is much easier to read.

Alan

[ValeryOchkov]

One more plot - it is not a physic but a numerical calculations error (?)

4) We need more interesting tasks!

AlanStevens wrote:

3. You are brilliant!

Alan

Thanks but not yet -only platinum:

[ValeryOchkov]

Oppppps!

The air density is a function of y - see http://en.wikipedia.org/wiki/Density_of_air

Now I am without Mathcad (with iPad). Alan, help me, please!

And second.

It will be good to have not 2 odes but 3 equations:

- a(t)=v'(t)

- v(t)=y'(t)

- -a(t)*m=...+...

[AlanStevens]

Valery Ochkov wrote:

Oppppps!

The air density is a function of y - see http://en.wikipedia.org/wiki/Density_of_air

Now I am without Mathcad (with iPad). Alan, help me, please!

And second.

It will be good to have not 2 odes but 3 equations:

- a(t)=v'(t)

- v(t)=y'(t)

- -a(t)*m=...+...

Sorry Valery, I've been away for a couple of days! Do you mean something like the attached?

Alan

[ValeryOchkov]

Thanks Alan!

1) mass=constant

See the attach

2) g=g(y)

[AlanStevens]

Valery Ochkov wrote:

Thanks Alan!

1) mass=constant

See the attach

2) g=g(y)

1) Of course!

2) At 3km, g is about 9 parts in 10000 smaller than at 0 km, so I'll leave this adjustment to you.

Alan

[ValeryOchkov]

Thanks, Alan!

And what about this task http://communities.ptc.com/message/188012

[ValeryOchkov]

Hi Alan!

Can we create in Mathcad a model of this fly:

http://www.bbc.co.uk/news/science-environment-19943590

[ValeryOchkov]

My first try to create the model of the fly the skydiver from 39 km:

[ValeryOchkov]

New ODE problem:

http://www.youtube.com/watch?v=nRkQE0I4NZw&feature=plcp

(5 friends from Harvard University decided to send a delicious hamburger to space. B.good, a local hamburger company in Massachusetts, was generous enough to help us out and sponsor this entire mission (check them out at www.bgood.com). That was their burger! They are awesome.)

[ValeryOchkov]

Valery Ochkov wrote:

New ODE problem:

http://www.youtube.com/watch?v=nRkQE0I4NZw&feature=plcp

(5 friends from Harvard University decided to send a delicious hamburger to space. B.good, a local hamburger company in Massachusetts, was generous enough to help us out and sponsor this entire mission (check them out at www.bgood.com). That was their burger! They are awesome.)

... and the Up-Fly of the Hamburger: