From: samik@maths.tcd.ie (Samik Sen)
Subject: Re: Rolemaster Rules Clarifications
Organization: Dept. of Maths, Trinity College, Dublin, Ireland.
Date: Thu, 15 Oct 1992 09:13:22 GMT

pvanheus@frodo.cs.uct.ac.za (P A van Heusden) writes:


>Standard tactic. Or: Cast leaving on boulder, leave on opponents head. We
>work this by having to use spell mastery for accuracy on the resultant
>spell. So its not so easy. Also, if you're talking about a low level magician
>using such a spell, no go. RR's are just too tough for a low level mage.
 
 But don't you use the rule in spell law for weights of targets of spells,
i.e.Caster can effect about 1.5 X weight of caster or whatever it was,so that
say the caster grabs onto another player and tries to leave both of them away,
in general s/he'll have to make an ESF roll based on how much extra weight
carried.So to cast leaving on a boulder of any reasonable size would surely
require an ESF which could be more risky than other options available.
 One option you could use is say for leaving,use a variant of another option
in spell law.It says you could allow giving multiples of concussion damage
by using multiples of PP.I.e. A 2nd level shock bolt cast with 10 PP(5X2) would
do times 5 hit point damage.Similarly a leaving spell cast with say 12PP which
is 4 times the 3PP in lofty bridge for leaving would allow you to move a weight
of about 6 times the caster's mass(approx) with no ESF roll,which could be about
350KG.Of course you'd probably want a spell mastery roll but this could be
of reduced difficulty if the mage actually practices this before combat etc
and actually uses it.
 The Problem for me though is how do you do the damage then...The complicated
way(i am a physicist trainee) is to say that leaving only moves it there so it
would not have any velocity,so know impact damage.You would in general of course
move it above there heads etc and they would have to carry 350KG,say and you 
could handle it as if they had 350KG in a backback and give the necessary 
encumberence penalty.If you move it above there heads,say 70 ft..about 20
meters.Then 

(Skip this if you don't like mechanics)
Potential energy is equal
to mgh=350*10*20,approx.This is equal to 70,000 joules of energy.The 
resulting kinetic energy would equal 1/2mv*v..use v*v=2gh and get v=sqrt(2gh)
v=sqrt(2*10*20)=sqrt(400)=20 meters per second.And the final maybe useful
info is it's momentum=mv=350*20=7000 units.(I know what they are but it is 
not necessary).Hmm,How to convert this to damage...The Area of the impact
surface is surely important since a sword has little momentum but little area to
so I think it reasonabe to say damage is proportional to momentum/area...If we
imagine the bolder to be of radius 1 meter then area=pi*r*r=about 3.So result
is 7000/3=2,300,approx,but wait.It's not that easy.The boulder may have an area
of about 3 but only a bit is hitting you...say the areas of your head which is
say .1 meter squared.So now get 23,000.now look at a sword of weight 6lbs,3kg say.Speed...
 You can throw a cricket ball,or serve in tennis at about 100 miles/per/hour.
Say swing sword tip at about 50 mph,or sword on average at 30mph(approx).
In  meters this is...1600 meters in a mile.So 48000meters/per hour.3600 seconds
in an hour->48000/3600meters per second=480/36=120/9=13(approx)Area is about
1 meter long,and thin wide.. Momentum is 13*3=39.Say 2 mm wide,so get 
39/0.002=39*500=40*500-500=19500,about.
(start again)

 So a 350Kg boulder does 23,000 damage if dropped from 70ft while compared to
19,500 from a full hack from a longsword from behind say(i.e. at optimum).If
the boulder hits you'll take an F crit,Crush.If the person sees it coming
it'll be easy enough to dodge since it will take the boulder(s=ut+1/2at*t->
20=1/2*10*t*t->t*t=4->t=2)2 seconds to make the fall.So to be realistic,a
boulder hit can do more damage than a sword but is a lot easier to dodge.IF
you take 4000 points to be a crit of 1 severity,so a sword doing 19,600 is
an E etc...I'd say make a roll,if you dodge it missed,else you take an F.