NTNUJAVA Virtual Physics Laboratory
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Easy Java Simulations (2001- ) => Questions related to EJS => Topic started by: ahmedelshfie on October 27, 2010, 11:40:20 pm



Title: Air Drag
Post by: ahmedelshfie on October 27, 2010, 11:40:20 pm
Hello prof
Could some help about Air Drag applet,have some bugs i tried solve but didn't have luck!
Have wrong in K1,K2 and graphic not totally right have many wrongs.
When i set value in k1 or k2 or both applet move so fast with a big error!
Help prof  :'(
Thanks



Title: Re: Air Drag
Post by: Fu-Kwun Hwang on October 29, 2010, 05:00:54 pm
Please at least provide the parameters which you think it does not function preporly.
Is it the same in my original applet or it only shown in your modified version?


Title: Re: Air Drag
Post by: ahmedelshfie on October 29, 2010, 05:25:24 pm
Hi prof
As long time ago you help me modified your original applet but,
Have many days i was check applet together teacher physic, i find many bugs i tried to solve this bugs.
Have bugs in k1,k2,graphic of x,y
Because it i ask if you could check applet and help me solve this bugs.
Thanks prof


Title: Re: Air Drag
Post by: Fu-Kwun Hwang on October 29, 2010, 05:47:07 pm
Would you explain what do you mean by something wrong in graphic of x-y
and what kind of bug in k1,k2?
What kind of values you have tried which you think it move too fast?

I need to know the parameters you have tried which you suspect there is something wrong,
so that I can re-product the same result you found.


Title: Re: Air Drag
Post by: ahmedelshfie on October 29, 2010, 06:02:07 pm
About bugs K1,K2 normally when i run applet appear value of k1,k2 zero but when i change
Value for example k2 i change value to 1,000000 to click Play so the mass move so fast and appear
Error in x,y value beside time, about graphic when i run applet still applet finish running i look to value of x,y
And check graphic of x and y i find different but i think wrong only in y, last thing is the mass after i set value of angle and velocity
I run applet so mass move normally still end when touch another point on other side must stop but not stop continue move but no always some times stop i think is like relationship between value of angle and velocity.  
(http://www.phy.ntnu.edu.tw/ntnujava/index.php?action=dlattach;topic=1984.0;attach=3540)


Title: Re: Air Drag
Post by: Fu-Kwun Hwang on October 29, 2010, 08:21:24 pm
There is nothing wrong with the code.

It is because you have too large value for k1,k2

The resistor force is assume to be $F=K1*V+K2*V^2$ and the mass is assumed to be 1.
K1 and K2 has to be much smaller than 1.
for k2=0.1 it is not an object moving in air. It is an object moving in densed fluid.


Title: Re: Air Drag
Post by: motazibrahim on November 05, 2010, 01:48:18 am
Thank you prof for help, so every thing alright and not have any wrong like i think.
This a count my brother i was check is still work or no
Ahmed
Thanks   ;D