From: mperry@waikato.ac.nz
Newsgroups: rec.games.frp.misc
Subject: Re: Strong??: was Re: META: Swords, etc
Date: 14 Nov 92 12:47:43 +1300
Organization: University of Waikato, Hamilton, New Zealand

> |> Some people look at the large figure (100lbs) and assume strong. 100lbs is
> |> quite heavy. Standard weights in NZ for something in bags commercially is 50kg
> |> or 110lbs. This is heavy, but the average person can pick them up, and with
> |> practice they can get used to doing it all day (several hundred times a day)
> 
> So what?  The point with swinging a sword is you have to do it very
> quickly, otherwise the other guy has already killed you.  The force you
> exert on an object is related to the mass of the object, and the speed
> with which you move it from rest to the desired velocity (ie:
> acceleration).  If you can pick up a 100lb bale of hay, it might take
> you a second to lift it, if you didnt want to rip your arms out of their
> sockets or stuff your back.  A swordsman would like to move his sword thru
> an arc in about 1/10th of a second or less.  ie: exerting a roughly
> equivilant amount of force, but in much less time.  Id call that strong.
Look back, the comments were about pulling on a bow string. Second, your
calculations are totally wrong - try recalculating them. 

A sword weighs 5 pounds?
Due to its mass and aerodynamics you can swing it fast. Due to it being an
edged weopon it hits with a lot of force - the harder it swings the more force,
the longer the sword, the greater the speed the tip moves at (again more
force). A good swords man doesn't need to be strong (as in real strong) because
they are only moving a small object (a sword with low mass), they do need
stamina, they do need accuracy, and they do need good reflexes. Try something,
swing a object that is 4-5 feet long and about 5 pounds - quite easy to swing
it fast - now for the strength test - swing it hard and stop it in mid flight
if you can. The most dangerous manouver for a swordsman was not created by the
opposition, but themselves. Swing a sword hard - it builds up inertia and to
stop needs an equal amount of force (hit something, or strength) so if you
swing, make sure you hit - otherwise while you are recovering from your wild
swing the other guy will skewer you. Try another - hold a 5lb 5foot rod strait
infront of you at shoulder height - notice it get heavy.

> Besides, Im quoting the linear force equation F=ma.  Swinging a sword
> thru an arc is more like an angular problem.  Im not sure what that
> equation is because I dont know the formula for working out the angular
> momentum of a long thing, but it probably works out as even harder.
Recalculate - it is easier than the bale of hay. You have a sword swinging in a
strait line with F=ma. You only need a small amount of sideways force to
make it into an arc (because it has small mass) - moving a bale of hay is
harder as it has much higher mass. So the new formula = F=ma(swing)+ma(arc).
You will need to adjust it for aerodynamics which change the equation
completely. Try swinging a sword - now try swing it again by turning the sword
slightly as you swing - it arcs.
Using the formula F=ma. and a bale of hay at 80lbs and a sword at 5 you would
need 16x as much acceleration on the sword as you get on the bale. To compare
the two you would need to calculate the acceleration of the hand position - not
the tip of the sword. How do you measure the acceleration though? The
aceleration on the bale of hay is very high - as the length of time that force
is applied is very short - just two or three jerks to move the 80lbs, while
with a sword you can keep the power of the thrust going right to when the sword
hits and beyond. The power of the sword doesn't rest with swing of the arm 
though, it relies on getting the momentum of the tip going - you could keep 
your arm almost stationery with only your wrist moving.

PS you have no idea about weight do you.
A bale of hay weighing 80lbs (about average) take a couple of seconds to get
ready (eg walking back from the last bale of hay), then you find the strings 
(slide your finger under them - still no use of strength), Then in one movement
you pick up the bale and swing it in the direction you want it and give it an
extra push to help it on its way. From the time you started picking up the bale
to when you have finished swinging and pushing the bale takes between 0.15
seconds and 0.3 seconds. If you are throwing the bale to a place 1 metre higher
than you then you need to change tactics - pickup and swing the bale above
shoulder hieght - before the bale starts coming back down give it the push to
get it the extra hieght (still under .4 seconds). You may still be holding the
bale longer than this, but you aren't using force. Only an Idiot would pick up
and carry a bale of hay if they don't have to. As for pulling your shoulders
out of joint - Get real. Back injuries, possible - but if you are fit then they
are less likely (I don't mean you can jog 1km without trouble, but can do
continued work like picking up hay all day), more likely to arise later in life
when your muscle turns to flab and you continue to lift heavy objects
sparadicly. Most back injuries are caused - not because someone was lifting a
heavy weight, but because someone was lifting a wieight heavier than their
fittness level (I'm not including lifting sports) supported. Eg a runner has no
fittness for lifting - so if they are going to lift moderately heavy weights
then they should build up to them slowly. Same applies to any area of fittness
that you don't have - build up slowly.
Newsgroups: rec.games.frp.misc