We also know that if v is his initial vertical velocity, then y=–2.3t²+vt+4 (the 2.3 comes from half the gravitational constant “g,” being roughly 2.3 Rocks per second squared). Writing t for time (and starting at time t=0), we know that x=ht+5, so t=(x-5)/h. Call it h (and note it’s negative because he’s going to the left). Get ready for a trip back to high school physics:
In plain English: How fast does he have to be running to make that jump? And is it within the realm of human possibility? Now we have to deduce the Rock’s necessary initial velocity. The parabola doesn’t solve our problem, though. Graphic by Matthew Zaremsky The Bigger Question: How Fast Is Johnson Going? If you made it through that, congrats! We just figured out the Rock’s parabola. This finishes the computation of the parabolic trajectory of the Rock: y=–0.1x²+1.3x. The first equation tells us that b=1–3a, and substituting this into the second equation tells us that 4=10a+5, so we have a=–0.1 and b=1.3.
Plugging in the other two points, we get the system of equations 3=9a+3b and 4=25a+5b. Since it contains (0,0), we know c=0, so really the equation is y=ax²+bx. Now it’s time to compute the parabola that connects Johnson’s starting point, end point and current position. (Zaremsky warns it’s hard to be more precise when we’re using a flying man on a movie poster as our unit.) Zaremsky hand-measured Johnson’s current mid-air position at roughly (3,3) and his starting point at (5,4) on a two-dimensional plane with an X and Y axis. ABlIwrjF6CĬall the under-the-window destination point (0,0), with 1 Rock as the unit of measurement.
He’s clearly not trying to land his feet in the window-that would just be cinematically lazy-so let’s say his destination is 1 Rock below the bottom of the window, so he can just barely grab hold of the edge, shattered glass be damned.įurther support for your theory that he is aiming for a one-handed grab at the bottom of the window. Next, we need to identify where he’s aiming. Johnson is 6-foot-5, so let’s give him a 7-foot span from his feet up to his raised hands. To solve this problem and find the Rock’s trajectory, we need to compute a parabola that connects three coordinates on the Skyscraper poster: Johnson’s destination, his current position and his starting point.įirst, we need a unit of distance. If the Rock can jump off a crane with a prosthetic leg to save his family-I know, I know, don’t cry-you can read through some advanced high school math.) Computing Dwayne Johnson’s Parabola (Sorry, I’m not giving you the answer just yet. A day later, he sent back a 650-word analysis, which I will attempt to parse for you here. I emailed a guy with a PhD: Matthew Zaremsky, an assistant professor of mathematics at the University at Albany, previously Cornell. Right? Right?Īpologies to the memers and the Twitter smartypants who actually tried to figure it out (spoiler: he’s not quite right), but I had to settle this issue once and for all without actually seeing the movie to find out. I mean, it sure looks like the Rock is about to die here. Whichever you choose, rest in peace The Rock, as you are dead now. Red is assuming he jumped up a bit first green assuming he ran forward and somehow didn’t lose momentum yellow for a sort of squat-thrust thing. I’ve mocked up some parabolas for The Rock’s SKYSCRAPER jump. The poster went viral and instantly became a meme when it debuted. There’s no reason to understand why the Rock is hurling himself off of a giant crane into a smashed-open window somewhere in the stratosphere-only that the internet’s armchair engineers have taken the image and tried to “debunk” it with parabolic diagrams surely sketched with a mouse in MS Paint. The trailer is chock-full of the standard Rock-brand running and rescuing, but we’re here to talk about the promotional image below, which manages to raise the stakes with a seemingly impossible vault. Skyscraper, the new Dwayne Johnson action movie opening July 13, has a plot so amazingly dumb only the Rock could make me type this sentence seriously: A former FBI agent-Johnson, of course, but inexplicably missing a leg-gets framed for a fire in a skyscraper with his family stuck inside. Look, if you thought calculus wasn’t useful for anything outside of your high school AP exams, you clearly haven’t spent 24 hours figuring out whether the Rock falls to his death trying to leap from a mile-high crane into the tallest building in the world.
0 kommentar(er)
