{"id":413965,"date":"2017-05-25T02:00:00","date_gmt":"2017-05-24T23:00:00","guid":{"rendered":"https:\/\/www.fyysika.ee\/?guid=54b60e2686dfd52435f3b88632cb39b0"},"modified":"2017-05-25T02:00:00","modified_gmt":"2017-05-24T23:00:00","slug":"the-bottle-flip-challenge-demystified-where-is-the-centre-of-mass-2","status":"publish","type":"post","link":"https:\/\/www.fyysika.ee\/?p=413965","title":{"rendered":"The bottle flip challenge demystified: where is the centre of mass?"},"content":{"rendered":"<p>Bodies can have very weird trajectories when tossed into the air. The amazing motion of a water<br \/>\nbottle flip is qualitatively described as related to the position of the centre of mass (CM) with<br \/>\nrespect to the body\u2019s frame of reference. Although this is rather easy to guess from simple<br \/>\nobservations, it is not so obvious to verify quantitatively with the naked eye. In this work, we use<br \/>\nvideo analysis and a computational model to show that the position of the CM changes in the frame of<br \/>\nreference of the bottle, while it describes a parabolic trajectory in the frame of reference of the<br \/>\nlaboratory. We also show that the behaviour of the CM also explains the weird motion of the bottle.<br \/>\nIt can be observed graphically and discussed in the classroom with students, as it only needs some<br \/>\ncritical thinking and practically no math.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Bodies can have very weird trajectories when tossed into the air. The amazing motion of a water<br \/>\nbottle flip is qualitatively described as related to the position of the centre of mass (CM) with<br \/>\nrespect to the body\u2019s frame of reference. Although thi&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_genesis_hide_title":false,"_genesis_hide_breadcrumbs":false,"_genesis_hide_singular_image":false,"_genesis_hide_footer_widgets":false,"_genesis_custom_body_class":"","_genesis_custom_post_class":"","_genesis_layout":"","footnotes":""},"categories":[178],"tags":[],"class_list":{"0":"post-413965","1":"post","2":"type-post","3":"status-publish","4":"format-standard","6":"category-rss-fuusikaharidus","7":"entry"},"_links":{"self":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/413965","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=413965"}],"version-history":[{"count":0,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=\/wp\/v2\/posts\/413965\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=413965"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=413965"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.fyysika.ee\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=413965"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}