Kindergarten Energy - Part 2

http://www.thestar.com/article/653925

A 7-year-old boy … was struck by a car at a Cabbagetown crosswalk. The boy was riding a bicycle … the (car in the) curb lane continued and struck him," said Const. Mig Roberts.

Please see also Kindergarten Energy - part 1 and http://www.thestar.com/article/654192 .

It is why our law-makers have asked parents to raise their children to walk their bicycles across pedestrian crosswalks.

Humans have evolved to be what they are. We are bipedal. We walk upright. We don’t have to think about walking (after age two). We just walk.

(As an experiment, try dictating every part of every step out loud: “Tighten thigh muscles to raise right leg and foot above the ground. Rock forwards slightly on ball of left foot to tilt body beyond center of gravity, tighten knee muscles of right leg to fling the shin bones and foot outwards; move the ankle and foot bones to prepare the right foot for a cushioned landing in front of the body, transfer weight to the ball of the landed right foot. Tighten muscles to raise the left leg and foot above the ground,…” and so on. You’ll not get very far.)

We walk with a reflex action, an instinct if you will, a programmed action if you prefer. It is hard-wired into our brains. It is how we have evolved. Our brain circuitry has an area that just brings it all together. Not for nothing do we utter the derisory comment “Can’t walk and chew gum at the same time!”.

We STOP WALKING with a reflex action. It is hard-wired into our brains. It is how we have evolved. If you have ever been walking along and had a gun pointed at you (I have) or had some other dramatic event take place, you’ll remember how you stopped “dead in my tracks”. We are evolved with reactions that can bring us to a halt quite literally in mid-stride. We sometimes stop so suddenly that we fall over, or fall to one side. Stopping suddenly while walking is one of the things we are really very good at.

Sadly, we did not evolve with bicycles. Bicycles are too recent an invention to have affected our evolution.

Stopping a bicycle is quite a different act from stopping walking.

Stopping a bicycle requires that we shift our hands to wrap around the brake lever, and that we squeeze the brake lever on the handlebars, all the while steering a correct or changed course while applying as much pressure as possible, but not so much pressure that the wheels lock and we slide across the road surface.

There’s more, but I want you to believe that stopping a bicycle does not come as easily, nor can be as abrupt, as stopping walking.

Which is why it makes sense to walk a bicycle across a pedestrian crosswalk.

We have built-in instant-stopping when we are walking on two feet.

We DO NOT have built-in instant-stopping when we are pedaling with two feet.

Our inability to stop instantly (natural laws of evolution) coupled with the energy stored up in a moving bicycle (universal laws of physics) show us that our law-makers had their wits about them when they passed laws and urged us to obey them, when they asked parents to raise their children to walk their bicycles across pedestrian crosswalks.

Parents ought to pass this reasoning on to their children.

If I could teach a child nothing else, I’d teach the ½ *m*v^2 law of energy for moving objects, and the ½ *m*v^3 law for moving fluids.

So many lives could be saved; so many injuries avoided.

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