Polar model builder in 6.01 gives invalid expression error for angular variables
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Polar model builder in 6.01 gives invalid expression error for angular variables
 September 15 at 2:28:PM

Tammy Humphrey
5 Posts

I am trying to build a polar dynamic model to track an object rotating on a record player. If I include theta or omega in my expression for the force function fr I get the error message "invalid expression: unable to parse" (the variable vr works).

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 04 2:04:AM

Tammy Humphrey
5 Posts

Would anyone have any ideas about how I could resolve this issue with polar models? I was hoping to get my students to model rotation for an assignment this week... ...it's pretty hard for any but the most capable to do without using polar coordinates. Would be grateful for any suggestions! Thanks.

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 04 2:19:AM

Tammy Humphrey
5 Posts

Just tried installing the previous version of tracker  polar models work in that version for me.

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 04 3:29:AM

Douglas Brown
333 Posts

This issue will be fixed in the next release, which should be within a week or so. Doug
> I am trying to build a polar dynamic model to track > an object rotating on a record player. If I include > theta or omega in my expression for the force function > fr I get the error message "invalid expression: unable > to parse" (the variable vr works).

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 07 9:47:AM

Tammy Humphrey
5 Posts

Thank you so much Douglas, that's fantastic, I'll let my students know.

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 08 3:30:AM

Wolfgang
146 Posts

Tracker Online is a JavaScript version or Tracker and this version already has the polar model builder bug fix.
https://tracker.physlets.org/trackerJS/

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 18 1:23:AM

Tammy Humphrey
5 Posts

Thanks so much for your time, that's great to know.

Re: Polar model builder in 6.01 gives invalid expression error for angular variables  October 19 6:25:PM

Wolfgang
146 Posts

Version 6.0.2 of Java Tracker has been released and this version has the polar coordinate bug fix.

