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Geek Trivia: The Quibble of the Week for Dec. 4, 2007

This week's quibble comes from the November 28 edition of Geek Trivia, "Roller (coaster) derby." My own personal physics fact-checker, <b>Bill Ward</b>, once again nailed me on a slip in Newtonian technobabble.

If you uncover a questionable fact or debatable aspect of this week's Geek Trivia, "(Sonic) boom or bust," just post it in the discussion area. Every week, yours truly will choose the best quibble from the assembled masses and discuss it in a future edition of Geek Trivia.

This week's quibble comes from the November 28 edition of Geek Trivia, "Roller (coaster) derby." My own personal physics fact-checker, Bill Ward, once again nailed me on a slip in Newtonian technobabble.

"Sorry, Jay, but you've got a mistake in there; by definition, a pure Gravity coaster can't do negative Gs... it can only do >=0 G, unless there are inversions. I can't think of any possible reason that an escape coaster would need an inversion, so your negative G-force comment [about the Orion Emergency Egress System] is incorrect."

I really ought to start running all my articles by Bill first. Yes, I conflated the terms zero-G and negative-G -- my mistake. Thanks for the physics lesson, and keep those quibbles coming.

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About

Jay Garmon has a vast and terrifying knowledge of all things obscure, obtuse, and irrelevant. One day, he hopes to write science fiction, but for now he'll settle for something stranger -- amusing and abusing IT pros. Read his full profile. You can a...

6 comments
JamesRL
JamesRL

When coaster goes down quickly you feel positive G, you are pressed in your seat harder than gravity alone. When you speed up the next peek and the then at the apex you are feeling lighter than normal - you rise up off the seat because your body's momentum is going up while the car is flat. What is that then G wise? True its a fast transitional state. James

OnTheRopes
OnTheRopes

I don't think there ARE other peaks so no negative G-forces.

Dr. Tarr
Dr. Tarr

...but what is it called when a coaster does the little hump in the track without inverting. You still get an inertia based sensation of weightlessness, and if the coaster has the wrap around wheels that keep the car on the track, and an over the shoulder harness to keep you in the car, you can feel a force that certainly seems to be negative G, i.e. you are pushed (actually thrown) firmly into the top of the harness.

Dr. Tarr
Dr. Tarr

... that the sensation I described is negative G and is not related to inversion. In fact, if a similar maneuver was performed inverted it would seem like positive G relative to the rider. This begs the question: "When determining G whose perspective is used?"

Wally Bahny
Wally Bahny

You just need to stop writing about anything that could be related to physics. That would fix the problem... :-)

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