{"id":467,"date":"2024-12-04T08:00:00","date_gmt":"2024-12-04T07:00:00","guid":{"rendered":"https:\/\/control-advent.com\/?p=467"},"modified":"2024-12-06T15:45:00","modified_gmt":"2024-12-06T14:45:00","slug":"04-saving-christmas-in-australia-the-upside-down-tree-challenge","status":"publish","type":"post","link":"https:\/\/control-advent.com\/?p=467","title":{"rendered":"04 &#8211; Saving Christmas in Australia: the Upside-Down Tree Challenge"},"content":{"rendered":"\n<p><strong>Author of this question:<\/strong> Steffi Knorn, <em>Fachgebiet <em>Regelungstechnik<\/em>, <\/em>Technische Universit\u00e4t Berlin, Germany<\/p>\n\n\n\n<p>Santa wants to make Christmas extra special for kids in Australia by creating an upside-down Christmas tree. However, the unusual design keeps tilting over, and without a solution, the kids down-under might lose their festive cheer. To tackle the issue, Elf Shaz built a magical kart capable of moving in any direction\u2014left, right, forward, or backward\u2014and designed to sense the tree&#8217;s tilt. The situation sparked a heated debate in the workshop: how should Santa use the kart to keep the tree balanced? <\/p>\n\n\n\n<p>By the way: Elf Ava suggested trying to balance a broomstick or pen on their hand as an experiment to better understand the problem. On the other hand, Elf Hans, ever safety-conscious, warned them to exercise caution to avoid accidents or breaking things. Maybe that\u2019s some good advice to follow? What do you think?<\/p>\n\n\n<div class=\"wp-block-image\">\n<figure class=\"aligncenter size-full is-resized\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"1024\" src=\"https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024.jpg\" alt=\"\" class=\"wp-image-417\" style=\"width:auto;height:600px\" srcset=\"https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024.jpg 1024w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-300x300.jpg 300w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-150x150.jpg 150w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-768x768.jpg 768w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-640x640.jpg 640w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-24x24.jpg 24w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-36x36.jpg 36w, https:\/\/control-advent.com\/wp-content\/uploads\/2024\/11\/04-Dec-2024-48x48.jpg 48w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n<\/div>\n\n\n<p>a. \ud83c\udf84\ud83d\udd17\ud83d\ude9c Santa should instruct the kart to move right, left, forward, or backward whenever the Christmas tree tilts in that direction. This will solve the problem of balancing it on the spot. For situations where the tree needs to be relocated, attach a chain to the kart. This way, it can be pulled along while carefully adjusting the speed and direction to maintain balance during the movement.<\/p>\n\n\n\n<p>b. \ud83c\udf84\u2796\ud83d\ude9c Santa should instruct the kart to move right, left, forward, or backward whenever the Christmas tree tilts in that direction. For situations where the tree needs to be relocated, attach a bar to the kart. This allows for an initial push in the opposite direction of the intended movement before pulling it along. Be sure to carefully adjust the speed and direction while pulling to maintain balance during the relocation.<\/p>\n\n\n\n<p>c. \ud83c\udf84\ud83d\udce6\u274c Santa should use the kart to balance the tree in place as described earlier. However, there is no way of moving the tree around. Since the kart cannot be used to move the tree, the delivery will need to be organised differently, probably with the tree being transported in a box as usual. <\/p>\n\n\n\n<p>d. \ud83c\udf84\ud83c\udfe0\ud83d\udd04 Santa should use the kart to balance the tree on the spot, as described earlier. Luckily, this will only be necessary during the installation of the tree in Aussie homes. After a few minutes, the kart can be removed and reused in the next house. <\/p>\n\n\n\n<p>e. \ud83c\udf84\ud83d\udd29\ud83d\udee0\ufe0f Santa should ask Elf Billy to secure the tree to the kart using nuts, bolts, and sturdy steel. It&#8217;s the only reliable solution to ensure the tree stays in place. <\/p>\n\n\n\n<p>f. \ud83c\udf81\ud83d\ude9c\ud83c\udf89 Santa should gift the kart to the kids in Australia. While it may not solve the problem of the upside-down Christmas tree, the kart itself would make a wonderful present. <\/p>\n\n\n\n<p>g. \ud83c\udf84\ud83c\udfc4\ud83c\udf81 Santa should skip the kart and gift surfboards instead: they are perfect for an Aussie Christmas!<\/p>\n\n\n<div class='bootstrap-yop yop-poll-mc'>\n\t\t\t\t\t\t\t<div class=\"basic-yop-poll-container\" style=\"background-color:#b70004; border:0px; border-style:solid; border-color:#b70004; border-radius:0px; padding:10px 10px;\" data-id=\"9\" data-temp=\"basic\" data-skin=\"minimal\" data-cscheme=\"black\" data-cap=\"0\" data-access=\"wordpress\" data-tid=\"\" data-uid=\"f129b65d04dbe99cfaf282227e3bda3e\" data-pid=\"467\" data-resdet=\"percentages\" data-show-results-to=\"\" data-show-results-moment=\"never\" data-show-results-only=\"false\" data-show-message=\"true\" data-show-results-as=\"bar\" data-sort-results-by=\"as-defined\" data-sort-results-rule=\"asc\"data-is-ended=\"0\" data-gdpr=\"no\" data-gdpr-sol=\"consent\" data-css=\".basic-yop-poll-container[data-uid] .basic-vote { text-align: center; }\" data-counter=\"0\" data-load-with=\"1\" data-notification-section=\"top\"><div class=\"row\"><div class=\"col-md-12\"><div class=\"basic-inner\"><div class=\"basic-message hide\" style=\"border-left: 10px solid #008000; padding: 0px 10px;\" data-error=\"#ff0000\" data-success=\"#008000\"><p class=\"basic-message-text\" style=\"color:#000000; font-size:14px; font-weight:normal;\"><\/p><\/div><div class=\"basic-overlay hide\"><div class=\"basic-vote-options\"><\/div><div class=\"basic-preloader\"><div class=\"basic-windows8\"><div class=\"basic-wBall basic-wBall_1\"><div class=\"basic-wInnerBall\"><\/div><\/div><div class=\"basic-wBall basic-wBall_2\"><div class=\"basic-wInnerBall\"><\/div><\/div><div class=\"basic-wBall basic-wBall_3\"><div class=\"basic-wInnerBall\"><\/div><\/div><div class=\"basic-wBall basic-wBall_4\"><div class=\"basic-wInnerBall\"><\/div><\/div><div class=\"basic-wBall basic-wBall_5\"><div class=\"basic-wInnerBall\"><\/div><\/div><\/div><\/div><\/div><form class=\"basic-form\"><input type=\"hidden\" name=\"_token\" value=\"b4267f7fda\" autocomplete=\"off\"><div class=\"basic-elements\"><div class=\"basic-element basic-question basic-question-text-horizontal\" data-id=\"9\" data-uid=\"4c6a90738a55742aa96b9b907efc4307\" data-type=\"question\" data-question-type=\"text\" data-allow-multiple=\"no\" data-min=\"1\" data-max=\"1\" data-display=\"horizontal\" data-colnum=\"\" data-display-others=\"no\" data-others-color=\"\" data-others=\"\"><div role=\"heading\" aria-level=\"5\" class=\"basic-question-title\" style=\"color:#ffffff; font-size:14px; font-weight:normal; text-align:center;\">Choose an option:<\/div><ul class=\"basic-answers basic-h-answers\"><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"43\" data-type=\"text\" data-vn=\"82\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[43]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[43]\" name=\"answer[9]\" value=\"43\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">a<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"44\" data-type=\"text\" data-vn=\"167\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[44]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[44]\" name=\"answer[9]\" value=\"44\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">b<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"45\" data-type=\"text\" data-vn=\"32\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[45]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[45]\" name=\"answer[9]\" value=\"45\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">c<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"79\" data-type=\"text\" data-vn=\"16\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[79]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[79]\" name=\"answer[9]\" value=\"79\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">d<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"80\" data-type=\"text\" data-vn=\"15\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[80]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[80]\" name=\"answer[9]\" value=\"80\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">e<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"81\" data-type=\"text\" data-vn=\"4\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[81]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[81]\" name=\"answer[9]\" value=\"81\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">f<\/span><\/label><\/div><\/li><li class=\"basic-answer col-xs-6 col-sm-6 cols-7\" style=\"padding:0px 0px;\" data-id=\"82\" data-type=\"text\" data-vn=\"6\" data-color=\"#000000\" data-make-link=\"no\" data-link=\"\"><div class=\"basic-answer-content basic-text-horizontal\"><label for=\"answer[82]\" class=\"basic-answer-label\"><input type=\"radio\" id=\"answer[82]\" name=\"answer[9]\" value=\"82\" autocomplete=\"off\"><span class=\"basic-text\" style=\"color: #ffffff; font-size: 14px; font-weight: normal;\" tabindex=\"0\">g<\/span><\/label><\/div><\/li><\/ul><\/div><div class=\"clearfix\"><\/div><\/div><div class=\"basic-vote\"><a href=\"#\" class=\"button basic-vote-button\" role=\"button\" style=\"background:#ffffff; border:1px; border-style: solid; border-color:#000000; border-radius:0px; padding:5px 10px; color:#000000; font-size:14px; font-weight:normal;\">&gt;&gt;&gt;<\/a><\/div><\/form><div class=\"yop-poll-modal\"><div class=\"yop-poll-modal-content\"><div class=\"yop-poll-modal-header\"><span class=\"yop-poll-modal-close\">&times;<\/span><\/div><div class=\"yop-poll-modal-body\"><div class=\"yop-poll-form-group\"><label class=\"yop-poll-user-or-email-label\">Username or Email Address<\/label><input type=\"text\" class=\"yop-poll-user-or-email-input\" autocomplete=\"off\"><\/div><div class=\"yop-poll-form-group\"><label class=\"yop-poll-password-label\">Password<\/label><input type=\"password\" class=\"yop-poll-password-input\" autocomplete=\"off\"><\/div><div class=\"yop-poll-form-group submit\"><button class=\"button button-primary button-large yop-poll-login-button\">Log In<\/button><\/div><div class=\"yop-poll-form-group yop-poll-section-login-options\"><p><a href=\"https:\/\/control-advent.com\/wp-login.php?action=register\" target=\"_blank\">No account? Register here<\/a><\/p><p><a href=\"https:\/\/control-advent.com\/wp-login.php?action=lostpassword\" target=\"_blank\">Forgot password<\/a><\/p><\/div><\/div><\/div><\/div><\/div><\/div><\/div><\/div>\n\t\t\t\t\t\t<\/div>\n","protected":false},"excerpt":{"rendered":"<p>Author of this question: Steffi Knorn, Fachgebiet Regelungstechnik, Technische Universit\u00e4t Berlin, Germany Santa wants to make Christmas extra special for kids in Australia by creating an upside-down Christmas tree. However, the unusual design keeps tilting over, and without a solution, &hellip; <span class=\"more-link\"><a href=\"https:\/\/control-advent.com\/?p=467\" class=\"readmore\">Continue reading<span class=\"screen-reader-text\">04 &#8211; Saving Christmas in Australia: the Upside-Down Tree Challenge<\/span><\/a><\/span><\/p>\n","protected":false},"author":4,"featured_media":417,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[22],"tags":[],"class_list":["post-467","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-english"],"_links":{"self":[{"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/posts\/467","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/control-advent.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=467"}],"version-history":[{"count":6,"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/posts\/467\/revisions"}],"predecessor-version":[{"id":997,"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/posts\/467\/revisions\/997"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/control-advent.com\/index.php?rest_route=\/wp\/v2\/media\/417"}],"wp:attachment":[{"href":"https:\/\/control-advent.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=467"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/control-advent.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=467"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/control-advent.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=467"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}