Friday, January 2, 2015

Centrifugal Versus Centripetal and a Picturesque Promenade

We walked around Lincoln Park today. First off, the way Mike described it was that it was longer and deeper in the woods than what was there. Second, the zipline at the playground was seriously fun because it had a hard stop and it made an adult me swing up until my legs were pointed toward the sky and I was leaned way back but still not falling out of the seat because of centrifugal force. Or is it centripetal? I can't remember.

Wait. I'm going to look it up.

Okay, I think I have this thing. When you're spinning on a merry-go-round, centripetal force is how hard you have to hold on to keep from flying off and landing on your butt. In my case on the zipline, the centripetal force was how hard that fat cable had to hold onto my butt in the swing to keep me from flying at a tangent to the circle I was spinning at the hard-stop-end. No flying off into the dirt. Yup. I thank the force that fat cable endured to hold onto the adult me. I know, I know. I looked a little ridiculous standing in line with all those little kids, but this thing was seriously fun.

Centrifugal is what happens when the fat cable doesn't have the tensile strength to hold onto my adult butt and inertia sends me flying, which it didn't. It's also what happens when your brother or your dad is spinning the merry-go-round too fast and your little fingers can't hold on and you go flying into the dirt, breaking that front tooth on a rock that was just supposed to be pretty and skinning both knees and the palms of your hands in the process. Yup, you can probably close your eyes and remember the feeling of that inertia and the friction required to stop you when it happened.

So, the lesson is that centripetal force is fun until your stomach rebels and you toss your cotton candy. Centrifugal force is simple inertia and usually hurts when you land after your short flight out of orbit.

 I was going to tell you about Lincoln Park.

It's late. I'm getting tired.

Here's the lowdown. It's more of a promenade along the Puget Sound than a hike. It's stunning to see and I'm glad we went. Imagine Alki beach only facing out toward the Olympic mountains. Today, it was clear and blue and the mountains looked like a row of low snow-tipped clouds on the horizon. Beautiful. Ferries and ships loaded with containers travel along the channel, made for picturesque scenes as the sun dropped over the mountains in the West. 

But it is well traveled and I felt like a dork with my fully-packed day pack.

I liked the bluff trail and there was a good geocache up there that we plundered. I surrendered my emergency blanket from my pack to the cause. It really wasn't as good as the coin we took, something we'll have to log on a geocaching website and send onto its merry way. It had a canoe on one side. An canoe! Maybe I'll carry it in my pack for the right moment since I'm usually the only one with a pack when we stop at a casual geocache.

And, after a good long walk, not a hike, I'm telling you, and another round on the zipline with the hard stop centripetal spin, we were on our way back home and trying to figure out what to do for dinner.

Here's the secret we learned for getting our fourteen-year-old son on and off the trail without a complaint: bring friends. He won't notice that he's getting any exercise.

Thank you for listening, jb

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