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Walter & Group...
[GH] For those of you who love to embrace physics and/or engineering, Walter Simbirski sends a technical description of curvilinear translation.
>From Walter:
Gordy -
Here is a somewhat technical but very good description of curvilinear translation:
The object may move along a curved path but if I draw a line between any two fixed points on the object
then draw another line between the same two points on the object at any time during a curvilinear translation of the object then the two lines will be parallel.
Hope that helps
Walter
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[GH] Walter,
Well.... I've finally learned what "curvilinear translation" really means.
Putting it crudely: "The object doesn't wobble as it moves forward in a curved path."
For most of our non-scientific instructors, your own translation of the physics into plain language will help most. You have a very special expertise in making these things understandable ! We're all grateful for that. It's a rare talent that I fear most scientists lack.
Gordy
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[GH] Because of an automated response to an email, I thought Mark Surtees had already left. As his message shows ..... he hadn't gone by the time our last message went out.
This from mark:
Hi Gordy
I haven’t quite gone yet…. J
At the heart of these questions is the issue that, in most cases when we cast, the rod moves through an angle and follows a curvilinear path simultaneously. Because two things co-occur doesn’t make them the same thing and this relationship doesn’t seem to be well understood nor does the interdependence of one on the other in order to achieve control over force, rod bend, tip velocity or tip path. If we are ultimately interested in teaching our students better control, then understanding how we can manipulate very basic elements of the cast to achieve particular objectives can only be beneficial.
I might have it all wrong, in which case I will be publicly eviscerated…which should be fun… J
Casting Arc and Casting Angle are used interchangeably in casting speak, you are right though, the parts of a circle are well established and so I like Angle better than Arc.
To make an object accelerate you don’t need to have an ever increasing force you just need to keep steadily applying it.
Pat has curvilinear translation pretty much bang on. It is only translation though, there is no rotation involved. Translation is not only in strictly straight lines.
Re Guy's question, strictly speaking, to rotate the rod we should be talking about “Torque” but I thought that might be even more confusing…, sorry ‘bout that,.. anyway this is measured in Foot Pounds or Newton Meters and it doesn’t really matter what size it is so long as its sufficient to overcome the inertia of the rod and line, which isn’t usually very much. If you carry on applying a torque fixed at X ftlbs over time/distance then the rod will accelerate through the Casting Angle.
Mark
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[GH] Mark,
I think that clarifies some issues. Between you and Walter, we're better armed with background information.
After a day or so, I'll send some of our answer messages for us to chew upon.
Meanwhile, have a great trip !
Gordy
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[GH] To those of you who have already sent your answers; if you should see fit to change any of them, go ahead and do so.
Gordy
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