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Community Tip - When posting, your subject should be specific and summarize your question. Here are some additional tips on asking a great question. X

yo-yo

ValeryOchkov
24-Ruby IV

yo-yo

I would like to create the digital double of  the yo-yo toy

Were is my error? See please attachs MC15 & Prime 5.

Do you know someone?

Thank you!

yo-yo1.png

25 REPLIES 25
LucMeekes
23-Emerald III
(To:ValeryOchkov)

Converted to Prime2

 

Luc

Thanks

But with error!

LucMeekes
23-Emerald III
(To:ValeryOchkov)

What error? It opens with no problems in my Prime 2 Express...

Sorry!

Prime Express can not work with the Odesolve function.

I have an error by Odesolve function in my Prime 5!

See please new version of sheets in attach.

Mathcad 15 gives as more informative error message.

Mathcad Prime 5 gives as old not informative error message.

Help please!

May be the math model is wrong?

If t.end is very small I have solution.

Now I have not 4 but 3 equation!

Help please!

See please attach

LucMeekes
23-Emerald III
(To:ValeryOchkov)

Prime 2 version attached.

 

Luc

sorry luc

I do not ask to convert 15 into prime

I ask to help  me   in solution

Hmm!  I'm not sure I like your yoyo Val, so I've come up with one of my own!  See below and the attached (M15 version):

 

g0.jpg

g1.jpgg2.jpg

 

Alan

 

I know! I know! I haven't included units.  I haven't provided an animation.  I haven't done the upward movement.  I'll leave that to whoever is interested! 

 

Thanks, Alan!

I am glad that I gave you the pleasure to solve this problem.

But I would like to see ODEs solution - not problem, but SuperProblem!

 

Why me sheets with Odesolve have errors?

Ok Val, I've modified your worksheet so that it works.  The solver was confused in particular by F(t) and the explicit inclusion of the energy equation (which is there implicitly in the other terms).  See my modifications below, and the attached for the complete file (M15).

 

g0.jpgg1.jpg

 

Alan

 

 

Great response!

 

Just one correction:

Capture.JPG

Not sure I understand Fred:

 

g2.jpg

Alan

 

Sorry!  I missed your substitution.  You (and Val, it seems) both assumed the string was wound on the outside of the yoyo.  You made no mistake, it was my omission.  What happens if the axle of the yoyo is much smaller than the outside of the yoyo?

Fred,

 

See my earlier reply above (reply number 9 I think), where I develop a model with the string attached to an axle.

 

Alan

Good one!

 

One more yoyo, Prime 4 express

Thanks? Alan and Fred!

But I would like know why my model with 4 equations not work.

Too few equations! Why? Prime 5 in attach!

Too-few.png

Too many initial conditions! Why? Mathcad 15 in attach.

Too-many.png

Deleted as irrelevant!

 

Alan

 

Sorry,Alan!

 

I have two 2-d order ODEs, not 4 1-st order ODEs

Deleted.  My previous comment here was beside the point!

 

Alan 

I've been thinking about this a little more.  My previous replies were too glib (i.e. wrong!).  I now think the problem is as follows:

 

g0.JPGg1.JPG

Alan

 

I have neither Mathcad 15 nor a full Prime, so OdeSolve is beyond me.

 

But, I think what you're missing is tying angular rotation together with vertical motion:

FredKohlhepp_0-1589544825892.png

 

One last addition:

 

Two full cycles and a string impulse calculation.

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