Suppose that the common figure of speech becomes literal and dead people literally roll in their graves when something extremely offensive to them happens somewhere in the world (to the effects of this question, dead people are aware of all occurrences of things that offend them).

A publishing house starts to churn out terrible young adult novels with extremely unimaginative worldbuilding, but with great commercial success (100 million copies sold in 10 years, a rough estimate of a Twilight-like rate).

The groundskeeper at Wolvercote Cemetery notices that J. R. R. Tolkien is rolling in his grave. Assume one revolution per novel copy sold.

How great would his energy output be? Could it be a worthwhile source of energy?


closed as off-topic by Vylix, Vincent, JBH, Slarty, L.Dutch Nov 23 '17 at 6:32

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  • "This question does not appear to be about worldbuilding, within the scope defined in the help center." – Vincent, Slarty, L.Dutch
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    $\begingroup$ You don't provide us enough information to answer this question. RPM alone isn't enough to calculate energy. $\endgroup$ – sphennings Nov 22 '17 at 21:12
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    $\begingroup$ @Bellerophon Knowing just mass and RPM gets us kinetic energy but that doesn't give us energy output. $\endgroup$ – sphennings Nov 22 '17 at 21:30
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    $\begingroup$ Unfortunately many individuals are cremated, and thus are not eligible for rolling in their grave. Secondly they only roll while in their grave. If you remove them from their grave, then logic dictates they would stop rolling. So the power generation mechanism would have to be built into the grave. $\endgroup$ – Anketam Nov 22 '17 at 21:46
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    $\begingroup$ @Bellerophon In theory given a high enough gear ratio and disregarding the material properties of the gearbox you could generate an arbitrarily large amount of energy from a single rotation. $\endgroup$ – sphennings Nov 22 '17 at 21:52
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    $\begingroup$ semi silly question, so semi silly answer in the comments. The standard wrist watch uses around .006 to .01 watt hours per year...I'll use 0.01 for simplicity. Now we can produce watches that power themselves, so I'd assume they'd have to generate through momentum enough to power that. A body has around 20 sq feet of territory to work with, assuming a 35mm watch, we should be able to cram 16 of these per square foot or around 320 jammed onto Zombie-Tolkien. gives us around 3.2 watt hours per year? Apparently wrist watch power generation isn't the way to go here. $\endgroup$ – Twelfth Nov 23 '17 at 20:14

The problem with this in terms of energy output is conservation of energy. In more conventional energy generation, we take energy in one form and convert it to another, far more 'useful' energy. Generally speaking, this means taking heat energy and converting it to movement (cars and trucks) or electricity.

The stored heat energy is in the form of coal, oil or gas. More recently we've been converting direct sunlight (heat) to electricity as well, and in Australia, we've been converting kinetic energy (rivers et al) into electricity for some time with systems like the Snowy River Hydro-electric system. Many other countries are using dams for exactly the same reason.

Why is all this important? Because even though we say we're 'generating' energy, we're not. We're really releasing the stored energy (or harnessing existing kinetic energy) in a form that can be used against a wide range of applications. In the example you're describing above, this won't happen. The amount of energy created by Tolkien rolling over in his grave would inherently be less than the energy used to print the book in the first place, not to mention laptop power used to write it in the first place, etc. Then there's Shipping Kilometres (look up Food Miles and Transition Cities to see the REAL cost of distribution in energy terms) and it becomes clear that you'd never get the same amount of power out of grave rolling as you'd need for the book production to do it, especially at a single roll per book sale.

Kindle might make that a little more efficient, but you couldn't power a kindle on the kinetic energy generated from a single roll. Particularly when you consider that a dead body will lose water pretty quickly, so the mass of a corpse would be substantially lower in time, meaning that the angular momentum of the roll would contain MUCH less energy...


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