{"id":70,"date":"2016-06-23T20:36:49","date_gmt":"2016-06-23T18:36:49","guid":{"rendered":"http:\/\/berndt-schwerdtfeger.de\/?page_id=70"},"modified":"2022-03-21T13:45:20","modified_gmt":"2022-03-21T12:45:20","slug":"astronomy-physics","status":"publish","type":"page","link":"https:\/\/berndt-schwerdtfeger.de\/?page_id=70","title":{"rendered":"Astronomy &#038; Physics"},"content":{"rendered":"<h3><a name=\"wave\"><\/a>Wave speed \/ Wellengeschwindigleit<\/h3>\n<ul>\n<li>version 1.0, 2014-10-31 : <a title=\"Wellengeschwindigkeit\" href=\"wp-content\/uploads\/pdf\/welle.pdf\">deutsch<\/a>, <a title=\"Wave speed\" href=\"wp-content\/uploads\/pdf\/wave.pdf\">english<\/a><br \/>MSC Primary 76B15, Secondary 76B20<\/li>\n<\/ul>\n<p>Die Rumpfgeschwindigkeit eines Verdr\u00e4ngerbootes wird definiert als die maximal erreichbare Geschwindigkeit und wird durch das bei der Fahrt erzeugte Wellensystem bestimmt.<br \/>\nSie ist proportional zur Quadratwurzel der Wasserlinienl\u00e4nge.<br \/>\nIn B\u00fcchern zur Seemannschaft findet man f\u00fcr die Rumpfgeschwindigkeit die Formel<br \/>\n<em>v = R * &radic;L<\/em><br \/>\nwobei <em>L<\/em> die L\u00e4nge der Wasserlinie und <em>R=2.43<\/em> wenn <em>L<\/em> in m und <em>v<\/em> in kn (Knoten = Seemeilen pro Stunde) gemessen wird.<br \/>\nIn diesem Artikel erkl\u00e4re ich den Faktor <em>R<\/em>.<\/p>\n<p>Diese Arbeit ist meinem Freund <em>Gerhard<\/em> gewidmet.<\/p>\n<p>The hull speed of a displacement boat is defined as the maximal attainable<br \/>\nspeed and is determined by the wave system generated by the displacement.<br \/>\nIt is proportional to the square root of the length of the waterline.<br \/>\nIn books on seamanship you find for the speed the formula<br \/>\n<em>v = R * &radic;L<\/em><br \/>\nwhere <em>L<\/em> designates the length of the waterline and <em>R=2.43<\/em> if <em>L<\/em> is measured in m and <em>v<\/em> in kn (knots = nautical miles per hour).<br \/>\nIn this article I explain the factor <em>R<\/em>.<\/p>\n<p>This work is dedicated to my friend <em>Gerhard<\/em>.<\/p>\n<h3><a name=\"sphere\"><\/a>Spherical design with METAPOST<\/h3>\n<ul>\n<li>version 2.0, 2016-02-28 : <a title=\"Sp\u00e4rische Zeichnungen mit METAPOST\" href=\"wp-content\/uploads\/pdf\/sphger.pdf\">deutsch<\/a><\/li>\n<li>version 2.0, 2016-02-28 : <a title=\"Spherical Design with METAPOST\" href=\"wp-content\/uploads\/pdf\/sphere.pdf\">english<\/a><br \/>first published: 2011-07-19<br \/>MSC Primary 70F15<\/li>\n<li>version 2.0, 2016-03-10 : <a title=\"Sphere drawings METAPOST code\" href=\"wp-content\/uploads\/mp\/sphere.mp\">MP code<\/a><\/li>\n<\/ul>\n<p>In diesem von <a title=\"Denis Roegel's Homepage\" href=\"http:\/\/www.loria.fr\/~roegel\/\" target=\"_blank\" rel=\"noopener\">Denis Roegel<\/a> inspirierten Artikel erkl\u00e4re ich mit etwas euklidischer Geometrie die Grundlagen zum Zeichnen von korrekten 2-dimensionalen Bildern von 3-dimensionalen Kugeln, insbesondere von Kreisen auf Kugeloberfl\u00e4chen (wie L\u00e4ngen- und Breitenkreisen) mit METAPOST.<\/p>\n<p>In dieser neuen Version 2.0 werden auch allgemeine Bahnprojektionen (etwa von Ellipsenbahnen) behandelt.<br \/>\nAn einigen Stellen wurden Rechnungen durch Konzepte ersetzt.<\/p>\n<p>Diese Arbeit ist meinem Bruder <em>Thomas<\/em> gewidmet.<\/p>\n<p>In this article inspired by <a title=\"Denis Roegel's Homepage\" href=\"http:\/\/www.loria.fr\/~roegel\/\" target=\"_blank\" rel=\"noopener\">Denis Roegel<\/a> I explain with some Euclidean geometry the basics of drawing correct 2-dimensional figures of 3-dimensional spheres, in particular circles on spheres (like circles of longitude or parallels of latitude) with METAPOST.<\/p>\n<p>In this new version 2.0 I also deal with general orbit projections (say of elliptical orbits).<br \/>\nOn several occasions calculations have been replaced by concepts.<\/p>\n<p>This work is dedicated to my brother <em>Thomas.<\/em><\/p>\n<h3><a name=\"solar\"><\/a>Inner Planets of Solar System<\/h3>\n<ul>\n<li>version 1.0, rev. 229, 2011-12-21 : <a title=\"week.pdf\" href=\"wp-content\/uploads\/pdf\/week.pdf\">2012<\/a> weekly positions of inner planets<\/li>\n<li>version 1.0, 2010-05-03 : <a title=\"solar.c\" href=\"wp-content\/uploads\/c\/solar.c\">solar.c<\/a> source code<br \/>first published: 2010-04-30<\/li>\n<li>version 1.1, 2022-03-21 : <a title=\"solar.pdf\" href=\"wp-content\/uploads\/pdf\/solar.pdf\">english<\/a> documentation<br \/>first published: 2010-04-30<\/li>\n<li>version 1.0, 2014-03-22 : <a title=\"sold.pdf\" href=\"wp-content\/uploads\/pdf\/sold.pdf\">deutsche<\/a> Dokumentation<br \/>first published: 2010-05-05<br \/> MSC Primary 70F15<\/li>\n<\/ul>\n<p>Dedicated to my wife <em>Carmen<\/em> on our wedding anniversary.<\/p>\n<p>In this paper I visualize the <em>orbits<\/em> of the <em>inner<\/em> planets: <em>Mercury, Venus, Earth <\/em> and <em>Mars<\/em>. Since <em>Kepler (1571-1630)<\/em> we know the shape of these curves: they are <em>ellipses<\/em>, which are here put into their relative position and orientation.<\/p>\n<p>The visualization is provided by a drawing with METAPOST. The presentation is at high school level, introducing ideas in a conceptual manner, though not losing sight of computation.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Wave speed \/ Wellengeschwindigleit version 1.0, 2014-10-31 : deutsch, englishMSC Primary 76B15, Secondary 76B20 Die Rumpfgeschwindigkeit eines Verdr\u00e4ngerbootes wird definiert als die maximal erreichbare Geschwindigkeit und wird durch das bei der Fahrt erzeugte Wellensystem bestimmt. Sie ist proportional zur Quadratwurzel der Wasserlinienl\u00e4nge. In B\u00fcchern zur Seemannschaft findet man f\u00fcr die Rumpfgeschwindigkeit die Formel v = [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":57,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"ngg_post_thumbnail":0,"footnotes":""},"class_list":["post-70","page","type-page","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/pages\/70","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=70"}],"version-history":[{"count":13,"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/pages\/70\/revisions"}],"predecessor-version":[{"id":894,"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/pages\/70\/revisions\/894"}],"up":[{"embeddable":true,"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=\/wp\/v2\/pages\/57"}],"wp:attachment":[{"href":"https:\/\/berndt-schwerdtfeger.de\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=70"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}