Cruisers Forum
 


Reply
  This discussion is proudly sponsored by:
Please support our sponsors and let them know you heard about their products on Cruisers Forums. Advertise Here
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 26-04-2015, 12:13   #106
Moderator Emeritus
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 5,486
Re: Physics Question

Quote:
Originally Posted by Adelie View Post
I make the divergence between the arc and a straight line tangents to be 180m or 363m depending on whether I approach from radius and cosine or travel distance and sin. See attached sketch.

Obviously one of them is incorrect. What I get for trying to do this while cooking crepes for breakfast and helping the 7yr old with her first crossword puzzle. She did pretty well with it, sharp as a tack, takes after her mother.

Then you factor in the moon's gravity and an initial cross-hole velocity and the hole diameter can get much smaller.

I figured your were an engineer or physicist, you were the only interested person finding my mistakes and extending the problem. What flavor of engineer? I'm civil.

Going back an extra post, the max declination of the moon is 18d17m or so, the earth's tilt to the sun is 23deg. Either way, drop when the moon is above the equator and no correction needed.
Ah, I see now. Turn the earth arc 90 and measure it from the barycenter. You will find that there is 0.8km between the two then.

I'm a hard headed mechanical engineer, though self trained. A pleasure BTW.
sailorchic34 is offline   Reply With Quote
Old 26-04-2015, 12:27   #107
Registered User
 
TeddyDiver's Avatar

Join Date: Aug 2010
Location: Arctic Ocean
Boat: Under construction 35' ketch (and +3 smaller)
Posts: 2,761
Images: 2
Re: Physics Question

Quote:
Originally Posted by Adelie View Post
Gravity Force Inside a Spherical Shell

If you need help working your way thru the math let me know.
Not needed thanks, done that as I said before
TeddyDiver is offline   Reply With Quote
Old 26-04-2015, 12:48   #108
Moderator
 
Adelie's Avatar

Join Date: Feb 2010
Location: La Ciudad de la Misión Didacus de Alcalá en Alta California, Virreinato de Nueva España
Boat: Cal 20
Posts: 20,590
Re: Physics Question

Quote:
Originally Posted by sailorchic34 View Post
Ah, I see now. Turn the earth arc 90 and measure it from the barycenter. You will find that there is 0.8km between the two then.

I'm a hard headed mechanical engineer, though self trained. A pleasure BTW.

Did that and and the result was the 180m value. I found a polar to Cartesian coordinate converter which confirmed the 180m value. Also it indicated the D value would be 41km.


Sent from my iPhone using Cruisers Sailing Forum
__________________
Num Me Vexo?
For all of your celestial navigation questions: https://navlist.net/
A house is but a boat so poorly built and so firmly run aground no one would think to try and refloat it.
Adelie is offline   Reply With Quote
Old 26-04-2015, 14:31   #109
Moderator Emeritus
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 5,486
Re: Physics Question

Quote:
Originally Posted by Adelie View Post
Did that and and the result was the 180m value. I found a polar to Cartesian coordinate converter which confirmed the 180m value. Also it indicated the D value would be 41km.


Sent from my iPhone using Cruisers Sailing Forum
Ah, I see autocad has a few minor bugs in it when used in large distances. I get 179.6 meters. You are correct.

Note to self, autocad needs the precision set properly when modeling large structures.

Oh the image is the buggy screen shot.
Attached Thumbnails
Click image for larger version

Name:	barycenter1.jpg
Views:	138
Size:	51.2 KB
ID:	100978  
sailorchic34 is offline   Reply With Quote
Reply


Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Challenge: Explain the Physics of Wind Over Tide Rex Delay Challenges 40 26-10-2015 07:09
The Physics of Sailing Video Kenomac Seamanship & Boat Handling 0 10-02-2014 06:54
KEEL/BALLAST QUESTION?? PLUS EXTRA CREDIT QUESTION ;) stephenronning Monohull Sailboats 3 21-03-2009 03:19
Physics, specs, and wind... Jack Long General Sailing Forum 23 22-07-2008 12:40

Advertise Here


All times are GMT -7. The time now is 06:15.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2024, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.