Re: (TFT) 1 point of 'damage' vs. 1 point of Fatigue

[Mark Tapley <mtapley@swri.edu>]

At 19:09 -0400 5/4/11, PvK wrote:
> * horsepower is a power measure, closer to force.

	Here's my breakdown on things:

	To Break:	To Move:
	---------	---------
Unit:	Energy		Momentum
Rate:	Power		Force


	Or in words, *breaking* a certain amount of stuff (armor, 
bones, skin, etc.) takes a certain amount of energy. *Moving* a 
certain amount of stuff (boxes, "pushing back" an opponent, etc.) 
takes a certain amount of momentum.

	How quick you can put energy into something (sword, punching 
bag, etc.) depends on how much Power you can generate.

	How quick you can change the momentum of something 
(wheelbarrow, door, etc.) depends on how much Force you can generate.

	Confusingly, the two columns are related by *distance* 
through which the force acts. This is what throws most people. A 
200-Newton force, applied to a nearly stationary object (like an 
ocean liner) will transfer momentum at the same rate as if it were 
applied to a highly mobile object (like an arrow). At the end of one 
second, both the ocean liner and the arrow will have 200 N-s of 
force. If you crunch on the unit N-s, it comes out to:

	(kg m/s^2) * s = kg m/s

which is mass times velocity, or momentum.
	The arrow, although it has the same *Momentum*, will have 
vastly more *Energy* than the ocean liner, because the 200-N force 
acted on it through a very long distance (because it started moving 
at the beginning of the second and kept accelerating all second long).

	So, to generate a lot of Energy quickly, you need *both* to 
put a lot of force on an object, *and* to keep applying the same 
force while the object moves a long way. There is an interesting 
trade-off having to do with the mass of the object - too light, and 
your arm (or whatever you are using to apply the force) can't move 
along with it. Too heavy, and the maximum force you can apply won't 
accelerate it much, so you can't put much energy into it in a given 
length of time.

	Conversely, a lever allows you to multiply the *force* you 
are applying to something, but *not* the Power you are putting into 
it! The higher force is counteracted by a slower motion of the short 
end of the lever, so the force * distance/time = Power is the same.

	I don't think it's possible to simplify the above much 
farther and stay consistent with real-world physics.

	Hope this helps.


--
						- Mark     210-379-4635
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