Where acceleration adds up

Sunday September 30, 2012

Q: If it’s not "motion sickness" you’re feeling at the amusement park, what is it? Isaac Newton and Albert Einstein would have applauded your more precise terminology.

A: Goose your car’s gas at a green light and you feel your body plastered back against the seat, as if "gravity were somehow pulling you down and backward at the same time," says Louis A. Bloomfield in "How Things Work: The Physics of Everyday Life."

When this happens, you’re actually experiencing the feeling of acceleration, as when starting up in a fast elevator or taking off in a plane. But nowhere is this feeling more pronounced than at an amusement park, where you can accelerate up, down and around on the carousel, back and forth in the bumper cars, or sideways in the scrambler.

The ultimate wild ride, of course, is the roller coaster, where you can go from feeling weightless as the car dives over the first big hill to an intense heaviness as it whips you around a sharp corner.

"Close your eyes on a straight stretch of highway and you can hardly tell the automobile is moving. But when you close your eyes on a roller coaster, you have no trouble feeling every last turn in the track. It’s not the speed you feel, but the acceleration. What is often called motion sickness should really be called acceleration sickness."

Q: "Sploosh! Whoops! I just dropped my smartphone in the toilet!"

What group did you just join?

A: According to a recent online survey, nearly one in five people have done this very thing, says Aaron Rowe in "Wired" magazine. The good news is that an invisible process of nanocoating "splash guards" your tweets from the commode or shower without interfering with microphones or speakers.

Just ship your device to a participating company that then places it in a vacuum chamber and pumps in a proprietary vapor to create a protective coating.

After Rowe had two different phones nanocoated, he described the results: "Amazingly, both survived repeated dunks in a sink -- not splashes but full immersions -- before finally giving up the ghost in a hot tub."

Q: Part of the fun of our mathematics is spotting the infinities hiding everywhere, such as when the whole number 1 is divided by the whole number 7.

So what infinities are to be found in the fraction 1/7?

A: Just divide 7 into 1 and you’ll get 0.142857... But don’t let that dot-dot-dot fool you. Following the 142857 is an infinite string of such series going in cycles, or 0.142857142857...

In fact, any whole number divided by 7 will yield either another whole number or an infinite string containing the repeated sequence 142857, as 100/7 = 14.2857142857...

Q: Why might a high-school kid earning good grades suddenly fail to turn in his assignments on time? And how does the word "tardigrade" fit in here?

A: As an A student among classmates getting mostly Cs and Bs, John G. of Laguna Woods, Calif., felt he stood out too much from his peers, reports Anu Garg in "Another Word a Day." So he began turning in his weekly theme papers a day late, prompting his teacher to assign him two grades, putting the "tardigrade" above a line and the "earned grade" beneath it. Since only the tardigrade was reported, his As fell to Bs and his Bs to Cs.

"Tardigrade" means "any of various tiny, slow-moving invertebrates of the phylum Tardigrada."

The term is from the Latin "tardigradus" (slow-moving), for "tardus" (slow) + "gradus" (stepping). Also from the same root are "retard" and "tardy."


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