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Paolo made a move I knew from dozens of townie soccer games played under lights on the fenced-in macadam pitch next to the elementary school in Badalucco, packed tight between Via Cristoforo Colombo and the bed of the Argentina River. Paolo twisted up his left leg; rotated that leg in an entirely autonomous and anatomically-impossible split-second burst of acetylcholine; power-rammed, with his left foot, the front bumper of our white cheese-tour van. A van, it now became clear, that Paolo had left precariously in neutral. With the parking brake disengaged. Tilted up along the road’s seriously steep grade. Its rear wheels inches from the verge, a sharp drop to the curve below. His cousin’s van, I remembered, as it lurched backward and gathered speed. Here’s the thing, often under-appreciated, about translational kinetic energy:
ET=(1/2)mv2

I’m quite certain that Hugo failed to fully apprehend the ramifications of this formula, given our weighty cheese van and his own position vis-à-vis an initially lumbering, but definitely accelerating, object. Perhaps Hugo had forgotten his boyhood physics class with its repeated exhortation that v = v0 + at.
Gravity, Hugo, gravity. 9.8 m/s² Hugo. But, most important: mass, Hugo. Mass. The van was heavy, no doubt about it, all by itself. Then you add all that luggage. Plus one 100 pound wheel of Parmigiano Reggiano. Plus Jack’s, or Lauren’s, or whoever’s six boxes of Canopic Cookie Jars. Plus whatever illicit items the Arbogasts had inserted into their collection. Plus nearly two weeks of accumulated detritus dumped on the floor by people who’ve spent way too many van-hours for the niceties of proper trash disposal to hold much sway. Plus Lauren. Maybe it was Lauren of whom Hugo was thinking when he jumped not away from but toward the rapidly-accelerating van, its front passenger door still gaping wide; a van that had by then about reached its tipping-point on the steep-shouldered roadside. Maybe it was Lauren. Or maybe Hugo had played linebacker for Texas A & M, back in the day, and still figured he was on top of his game, good to go, stop anything coming at him. But this was no 250 pound running back, Hugo. This was not even a steroidally-enhanced 350 pound running back. No. This was a stout door winged out from a 3000 kilogram white Fiat Ducato made weightier by its 20 gallon auxiliary tank full of used grease. So, let’s say three seconds elapsed between the moment when Paolo’s kick overcame the van’s inertia (and started ‘er rolling) and the instant when Hugo attempted to stop her. For ease of calculation, let’s put the inclined plane on which the Ducato rested at 45 degrees, i.e., pretty steep, and thus the parallel vector of gravity pulling her downhill at about 4.9 meters per second per second. After 3 seconds and change (we’ll ignore the rolling friction of axels and rubber tires) the Ducato would be chugging along at close to 15 meters per second. I think. Over 30 mph. Not so shabby. Which brings us back to ET=(1/2)mv2. 3000 kg at 15 meters per second. At the instant of contact, a direct hit would work on a firmly-planted Hugo with something in the vicinity of 337,500 Joules. Fortunately for Hugo, he was not planted, immovable, like the high-security bollard he believed himself to be, but more along the lines of a wobbly bowling pin. The door dealt Hugo a split-second glancing blow. What we probably need to figure here, as in football, is impact force per unit area. Newtons/m2. Stress. The specifics of this inelastic collision. Consult the law of cosines, maybe? You do the math, Hugo. Hugo was not going to be doing any math for quite a while. More or less simultaneously: I saw the open door plow into a Hugo determined to impede its progress. I heard the loudest noise I’d ever experienced. I saw the windshield explode in frost. I saw Paolo drop from sight. I heard Lauren scream. Then: I saw Hugo go down. I remembered Phil and Massimo. Under the backseat. Gliding toward oblivion.
Which must be when I made my own ill-advised lunge toward the driver’s seat, into the path of the open driver’s side door. A split-second later, as Pippa howled “Sybilla, don’t!” must be when I stumbled over a loose piece of rubble and myself went down. I’m told the bottom of the door just grazed my face. But, as noted, at 15 meters per second and rising, even a graze by a three ton vehicle can hit you with lots of Ns.

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closed as not constructive by dmckee Jan 25 '12 at 0:44

As it currently stands, this question is not a good fit for our Q&A format. We expect answers to be supported by facts, references, or expertise, but this question will likely solicit debate, arguments, polling, or extended discussion. If you feel that this question can be improved and possibly reopened, visit the help center for guidance.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Welcome to Physics.SE! I'm afraid that this is not a place for creative narrative at such length. If you have a question that conforms to the FAQ, please condense this to a concise statement of the problem. –  dmckee Jan 25 '12 at 0:45
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