Posts Tagged ‘physics’

Last year, I wrote a post about the physics behind a triple backflip in BMX.  Well, as most of you know by now, Josh Sheehan has done a triple backflip on a dirt bike.  If you haven’t seen the video, here it is:

Now that he’s done what we had thought would be the impossible (though we said that about the double before Travis did it), that leaves us with the question of whether there is a limit. Buzz Skyline did some calculations at his blog, eXtreme Sports Physics, and came up with a total of four flips.


Image from Buzz Skyline.  Click here for more images of his calculations.

Another physics blog, Physics Buzz, took a look at the front flip. While a backflip has the rider utilizing the bike’s natural momentum and the ramp’s angle (which shaves off half of the first rotation), a front flip combats those forces AND the landing is blind. As Jim DeChamp told ESPN, “[I]t’s not a natural beauty trick— it’s like, that is awkward, that is wrong.” The Physics Buzz post looks at both what happens when a front flip is executed properly and when things go wrong.

I’m pretty sure we’re not going to see a triple backflip in the X Games. The ramps just aren’t big enough. Who knows about the double backflip or the front flip, but my guess is that the new Quarterpipe event is going to take riders in the direction of off-axis flips and 360s. We’ll see.

“Where’s my hoverboard?” is something I often hear when people complain about things we should have already by now.  It’s become more common now that it’s 2015, the year in which Back to the Future Part II takes place.  Fear not, science has not completely broken its promise.

Last November, a video of Tony Hawk riding a Hendo Hoverboard prototype on a halfpipe surfaced.

I found the accompanying RIDE Channel article, which piqued my interest in the science behind the hoverboard. Although it brought up magnetic repulsion, the Hendo Hoverboard Kickstarter revealed that the physics are a bit complicated. After all, it’s nearly impossible to levitate one magnet on top of another without special conditions.

That’s also true for the Hendo Hoverboard, which is why it’s not quite ready for every day use. The board contains four magnetic engines. They generate eddy currents, which create a magnetic field in opposition to the field created by the engine. The opposing forces causes the board to be repelled by the surface. This is called Lenz’s law. Check out a smaller, more up-close example of how the engines work:

One big caveat to the hoverboard is the surface you ride on has to be made of a non-ferrous (does not contain iron) conductor. Therefore, you can’t ride it outside of the Arx Pax or a hypothetical “hoverpark”. Another issue, as seen with Tony Hawk’s ride, is control of the direction of travel. Despite having pressure-sensitive pads on the deck, the lack of friction makes it hard to figure out how much pressure to apply. It seems to be extra sensitive. Lastly, the biggest issue is that for now, we can only ride it for a few minutes before the battery runs out.

So we’re going to have to wait a bit before we all fly around on hoverboards. However, the idea of one has already made its way into reality. Moreover, we can take comfort in knowing that there are some things from Back to the Future Part II that did come true in a way.

The Perot Museum of Nature and Science is currently hosting a special exhibit called 2theXtreme: MathAlive!  It combines math, science, and engineering with action sports, design, and pop culture.  In other words, quoting the MathAlive! site, it “answer[s] the age-old question: ‘Will I ever use all this math they’re teaching us?'”  Last month, I got to check it as part of the museum’s adult-only Social Science event, which also featured a BMX demo.

Even though MathAlive! is designed for a younger audience, it still contains some fun hands-on activities and educational tidbits for adults.  Unfortunately we’re too big to enjoy the rock climbing wall and comfortably sit on the stationary bike (I have short legs and it was still awkward for me).  Several of the games seemed easy, but they still required some thinking.  This is a math exhibit after all!

My favorite part of the exhibit was the skateboard design challenge.  You selected board length, truck placement, and wheel size in order to create the ideal board for an ollie.  While it could have used a better explanation as to why a design failed, it was a cool way to look at a math problem.  My second favorite module was the 360-degree camera if only because I got this little souvenir:

Scattered throughout the exhibit were videos of people who use math, which range from engineers to video game designers to skateboarders.

I appreciated the diversity, particularly with the female scientists and engineers shown.  Women in math and science rarely get any face time, which negatively impacts girls thinking of getting into STEM fields. so I’m glad the exhibit is doing its part to promote equality.

The boardercross game should have been fun and easy, but the board was really rickety.  I didn’t utilize the rails because I wanted to emulate the real snowboarding experience.  Unfortunately I crashed too much in trying to get my balance.  Although it’s been over a decade since I stepped foot on a board, I can’t imagine my balance being that bad (I dance and still occasionally skateboard).  That was probably the most disappointing aspect of the exhibit for me.  Nevertheless the exhibit contained more ups than downs; just remember that it’s for kids and during regular hours, you’ll probably have to fight them to give each section a try.

Because I had to buy separate tickets for MathAlive!, I spent a lot of time there and didn’t get to see other aspects of Social Science.  I did catch the second freestyle BMX demo by BMX Pros Trick Team.  The riders have my admiration because not only did some of them come from doing demos all day at the State Fair, but they had to deal with low light and a moderately energetic (and somewhat inebriated) crowd.  Nevertheless, they still pulled out some of the big tricks.

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I tried to take photos, but it was too dark.

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This weekend, I discovered a show on The Science Channel called Outrageous Acts of Science.  It provides a snappy explanation behind the viral videos that have been collected based on a scientific topic.  Think Ridiculousness with scientists and engineers.

That’s why it shouldn’t have been a surprise that triple backflipping BMX rider Jed Mildon made it into the show. Physics has never been my forte so I’ll let the video do the talking. Plus you get to hear Jed’s point of view juxtaposed with explanations by the show’s experts. It really gives an overall picture of what it takes to complete such a feat.

This isn’t the first time physics has taken an interest in Jed’s video. Three years ago, Wired had an article explaining why no one had ever done a triple flip before (and why you still don’t see them today). Click here to check it out.

From Wired

From Wired

I had quite a few gripes about both the U.S. and Canadian coverage of Olympic snowboarding and freeskiing (and apparently my friends did as well).  It highlighted the inequality that’s rampant in both action sports and media, but that’s a post for another day.  Right now I want to focus on one of the good things that came out of this: the increased opportunity to explore the science behind skiing and snowboarding.  This is a great way to get action sports fans interested in science and scientists interested in action sports.

NBC paired with the National Science Foundation to create a series videos exploring the Science and Engineering of the 2014 Winter Olympic Games.  They’d done a similar series in 2010, but now they have gone past just a cursory coverage of sports, looking at halfpipe engineering and snow.  There’s also the addition of slopestyle skiing.

If you’re subscribed to The New York Times, you can get access to their interactive stories, which break down gold medal-winning runs and the keys to success.  They’re definitely worth checking out just for the composite photography.  Those without a subscription can catch some of the videos on Hulu.

The blog Physics Buzz did a podcast about snowboarding.  They explained the triple cork better than I ever did, and there’s a link to a post that breaks down the physics of one.

We can’t forget about the Paralympians, especially with the debut of boardcross this year.   Live Science shared an article about the technology that helps these athletes do things their able-bodied peers can do.  I want to take this time to congratulate Evan Strong for grabbing the first U.S. Paralympic gold in Sochi, being a part of the American sweep in men’s boardercross with Michael Shea and Keith Gabel, and making his way onto an upcoming Wheaties box:

Wheaties/Evan Strong

Finally, I came across a surprising mention to snowboarding while listening to the linguistic podcast, A Way with Words.  The term “wind down the windows” caught the attention of host Martha Barnette because it’s becoming a rather dated image (I remember winding down the windows in my dad’s old pick-up as a little kid).  It’s been pretty cool seeing and hearing snowboarding and freeskiing pop up in the most unexpected places.

I was excited to hear slopestyle get mentioned on the radio.  PRI’s The World previewed some of the events that will premiere at Sochi, and they asked a snowboarding instructor what to expect.  Now I don’t know if he was trying his hardest to avoid lingo and oversimplified things, but he said there will be “double backflips”.  When was the last time you saw a double flip at a slopestyle final?  At first I thought he was referring to the double cork, but he also said “corked maneuvers” so my guess is that he wanted to talk about spins.

Most people will probably think confusing spins and flips is an easy mistake.  However, a 720 is a completely different move from a double backflip.  Physics doesn’t have to be your strong suit (it’s definitely not mine) to see that.  When a snowboarder flips, they’re rotating around the X-axis.  For 360s, 720s, etc, the rotation is around the Y-axis.  As a result, the approach has to be different.  For a flip, the snowboarder leans back to generate torque whereas they have to start rotating their body during take-off for a 360 (due to conservation of angular momentum).  This also explains why backflips are generally viewed as easier.  The ramp helps give the snowboarder the pop upward.  On the other hand, they have to generate enough angular momentum to spin 360+ degrees while making sure they don’t veer off-course because they’re traveling in a completely different direction on the same axis.  In short, double backflips and 720s shouldn’t be confused for one another because of the physics involved.  Also, the judges will give you a totally different score.

I am glad the interviewee made a distinction with corked tricks since the physics for them is totally different.  Check out this Sport Science feature on the double cork 1080:

Since the video feature Shaun White, I would like to conclude with another point of inaccurate reporting. This weekend I kept seeing headlines about Shaun’s “new trick” or even “first-ever Cab double cork 1440 in competition”. Although it may be his first “YOLO flip” landed in competition and a new trick for him, Iouri Podladchikov did it at X Games Tignes Superpipe competition 10 months ago:

If we want to get super technical as to who did it first in competition, Shaun’s slopestyle teammate Sage Kotsenberg gets that honor. He did it at the Billabong Air and Style three years ago. You gotta be specific when you’re reporting!