{"id":10865,"date":"2016-08-31T11:51:48","date_gmt":"2016-08-31T15:51:48","guid":{"rendered":"http:\/\/scienceblogs.com\/principles\/?p=10865"},"modified":"2016-08-31T11:51:48","modified_gmt":"2016-08-31T15:51:48","slug":"physics-blogging-round-up-fast-cars-and-spherical-cows","status":"publish","type":"post","link":"https:\/\/chadorzel.com\/principles\/2016\/08\/31\/physics-blogging-round-up-fast-cars-and-spherical-cows\/","title":{"rendered":"Physics Blogging Round-Up: Fast Cars and Spherical Cows"},"content":{"rendered":"<p>It&#8217;s been a while since the last Forbes links dump, but since it&#8217;s the last day of the month, I figure I might as well sum up a bit. Only two posts, but they have a connection that I&#8217;ll expound on a bit to make up for the lack of material&#8230;<\/p>\n<p>&#8212; <a href=\"http:\/\/www.forbes.com\/sites\/chadorzel\/2016\/08\/25\/can-a-tesla-model-s-really-accelerate-faster-than-gravity\/\">Can A Tesla Model S Really Accelerate Faster Than Gravity?<\/a>: I got pointed to a story about the 0-60mph time for a Tesla, and said &#8220;That seems fishy&#8230;&#8221; After climbing back out of the Google rabbit hole, I tried to explain why that seemed unlikely to me, and the funny timing thing that might explain the result.<\/p>\n<p>&#8212; <a href=\"http:\/\/www.forbes.com\/sites\/chadorzel\/2016\/08\/29\/the-hardest-thing-to-grasp-in-physics-thinking-like-a-physicist\/\">The Hardest Thing To Grasp In Physics? Thinking Like A Physicist<\/a>: Some musings about how the trickiest part of learning to be a physicist is getting the mindset, particularly the highly reductionist use of &#8220;spherical cow&#8221; sorts of approximations.<\/p>\n<p>So, the first of these <em>really<\/em> pissed off a lot of Car Guys, who left tons of comments, and some angry emails and tweets, pointing to a variety of <em>other<\/em> cars that supposedly accelerate at large multiples of the acceleration of gravity. I wasn&#8217;t especially moved by most of this, in part because they&#8217;re not particularly relevant to the question of whether the Tesla result is surprising. It&#8217;s true that I didn&#8217;t discuss the possibility of aerodynamic down forces that would allow for a larger frictional force, but those aren&#8217;t actually important for a normal-ish car like a Tesla. A top fuel dragster is a completely different animal, and I&#8217;m not especially surprised that they work differently than an ordinary car.<\/p>\n<p>The other issue I have with the angry reaction is that it really misses the point of the post (which, admittedly, I probably should&#8217;ve made more explicit). That is, I don&#8217;t actually <em>care<\/em> whether the Tesla accelerates at 0.98<em>g<\/em> or 1.1<em>g<\/em>. My purpose in writing that piece, like most of what I write, really had more to do with the physics mindset than the specific numerical values. I was explaining my reaction and reasoning: when I read the original piece, I was immediately skeptical for reasons that have to do with physics, which sent me off looking for more information that might explain the faster-than-expected time in a way that didn&#8217;t require surprising physics, and learned about a timing thing that&#8217;s in the right ballpark to account for the apparent discrepancy. <\/p>\n<p>I thought that was an interesting process (obviously, or I wouldn&#8217;t&#8217;ve been sucked into Googling stuff about car testing), and worth laying out. I&#8217;m really not remotely invested in the specific numerical results&#8211; if the tires they use turn out to be much stickier than the usual run of things so the acceleration is a little higher than I would expect, well, that&#8217;s a nice bit of trivia. It doesn&#8217;t really change my thinking about why that was a piece worth writing, which is largely that it illustrates the toy-model-building described in the second post. Thinking like a physicist means that the 0-60mph time isn&#8217;t just a random factoid that could take on absolutely any value, it&#8217;s something with a physical origin that you can model in a simple way, which leads to an expectation about what the time <em>should<\/em> be for a relatively ordinary car. And thinking &#8220;that&#8217;s funny&#8230;&#8221; does, in fact, lead to something that&#8217;s a little funny in the timing, which is also interesting.<\/p>\n<p>But, yeah, I should&#8217;ve made that clearer, because, wow, are there people who are deeply invested in the accuracy of those numbers&#8230;<\/p>\n<p>Anyway, that&#8217;s the story of my recent blogging. Which may become sparse for the next several months, as I&#8217;ve gotten myself stuck on a grand jury that sits two days a week, and classes start next Wednesday, so my time is going to be very tight for the immediate future.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>It&#8217;s been a while since the last Forbes links dump, but since it&#8217;s the last day of the month, I figure I might as well sum up a bit. Only two posts, but they have a connection that I&#8217;ll expound on a bit to make up for the lack of material&#8230; &#8212; Can A Tesla&hellip; <a class=\"more-link\" href=\"https:\/\/chadorzel.com\/principles\/2016\/08\/31\/physics-blogging-round-up-fast-cars-and-spherical-cows\/\">Continue reading <span class=\"screen-reader-text\">Physics Blogging Round-Up: Fast Cars and Spherical Cows<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[5,6,7,11],"tags":[],"class_list":["post-10865","post","type-post","status-publish","format-standard","hentry","category-blogs","category-forbes-recap","category-physics","category-science","entry"],"_links":{"self":[{"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/10865","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/comments?post=10865"}],"version-history":[{"count":0,"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/10865\/revisions"}],"wp:attachment":[{"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/media?parent=10865"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/categories?post=10865"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/tags?post=10865"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}