Welcome to my new column, The Physics of Alagaesia, inspired by The Physics of Superheroes. In this column I will be analyzing the feats of power and endurance that characters in the Inheritance cycle perform. I’m choosing them randomly, and without many picked out yet, so if there is a particular scene you would like to see me discuss, please feel free to mention it.

We are going to start out with a small fragment of the battle that takes place in Brisingr between Eragon and Arya against however many hapless Imperial Fodder Pawns. I’ll probably be coming back to this scene a couple of times, because it has a lot of hilarious, but I’ll focus on a single segment for the moment.

Trapped, he did the one thing he could: he struck the man in the chest with all his might. A fount of blood and sweat erupted as his fist connected. The blow staved in the man’s ribs and propelled him more than a dozen feet over the grass, where he fetched up against another corpse. (p. 114)1

Calculations

Now, there are some things to note. This man is dressed in maille, and is a soldier besides. Let’s estimate the soldier at 200 pounds, or about 91 kg.2 The maille would be around another 10kg.3 So let’s call the total weight a nice even 100kg. Let’s call more than a dozen feet thirteen feet, although this might be low, because that will come out nicely to four meters. We’ll want to account for the force of friction here, and we’ll assume the grass isn’t already slick with blood, in which case mu = .35 should serve as a reasonable guide.4 Let’s draw the free-body diagram now.

We want to know just how strong Eragon’s arms are, so we are solving for Fpunch. Our first task is to determine what kind of initial velocity would be necessary to propel the soldier four meters. The deceleration due to friction is

g * mu = 3.5 m/s2

So we can solve the equation for initial velocity, v0.

v0 – 3.5t = 0
???

Here we encounter a problem. We need to know how long the man travelled before collapsing to the ground. The best we can do at this point is do some armchair calculations. We set up a second equation, describing the distance travelled.

4 = v0 t – 3.5 t2

If we attempt to solve this for t using the quadratic formula, we’ll notice something. We only have real results when

sqrt(v02 – 56) >= 0

Since I’m trying to favor Paolini at every single turn here, we’ll try and take the very lowest bound value. So, v 0 = sqrt(56) = 7.5 m/s. Now then, let’s determine what kind of force Eragon needs to exert to accelerate a man to that speed.

Guesstimating that the impact time of a punch is a tenth of a second, although a much shorter duration is possible (in which case Eragon would be even stronger), then Eragon is exerting a force of

(7.5)/(.1)*100 = 7500 Newtons

Interpretation

So Eragon can lift 750 kg, at minimum, since our calculations assumed the lowest possible numbers everywhere we could. 750 kg is close to 1650 lbs, and this is with one arm. This isn’t the full extent of the our favorite Gary Stu’s power, of course. By adjusting numbers in our estimation, we could easily have him lifting 12,000 lbs, but we wouldn’t do that, would we?

Next time around, we will calculate how far Arya can jump, and why she should have been able to escape from Durza.

1 Brisingr

2 http://pediatrics.about.com/cs/growthcharts2/f/avg_wt_male.htm

3 http://homepage.ntlworld.com/trevor.barker/farisles/guilds/armour/mail.htm

4 http://hypertextbook.com/physics/mechanics/friction/

Comment

  1. Kitty on 17 February 2009, 00:05 said:

    I said it before and I’ll say it again…you’re a gigantic nerd.

  2. SlyShy on 17 February 2009, 00:07 said:

    Guilty as tried. What shall my sentence be?

  3. LiquidNitrogen on 17 February 2009, 00:14 said:

    Wow…love the diagrams.

  4. LiquidNitrogen on 17 February 2009, 00:16 said:

    Sorry for the double post, but I was wondering if you could average out the amount of calories it would take for Roran to kill 193 soldiers. It’ll probably be a very tough calculation, but can you do it?

  5. Spanman on 17 February 2009, 00:20 said:

    I was completely lost, buuuut it’s very amusing all the same. ^^

  6. SlyShy on 17 February 2009, 00:29 said:

    LiquidNitrogen,

    It’s something I’m interested in as well, but it’d be very difficult for me to come up with anything that was more accurate than wild speculation. I guess I could try and equate his level of activity to that involved in some other sport. American Football might be a valid comparison.

  7. Kitty on 17 February 2009, 01:28 said:

    Your sentence is YOU HAVE TO CLEAN MY KITCHEN

    It’s a mess.

    Anyway, fig. 1 is the best one. Eragon’s all like “POW” and the soldier’s all like “OH EXPLOITABLE”. Awwwwww.

  8. SlyShy on 17 February 2009, 01:33 said:

    My art teacher will be so proud.

  9. Artimaeus on 17 February 2009, 01:33 said:

    According to this webpage, http://www.nutristrategy.com/activitylist.htm fútbol americano burns about 633 calories an hour, assuming Roran weighs about 155 lbs, which seems about right for a poor, medieval farm boy. Now because football players spend about half of their time on the bench, let’s multiply that by two.

    So after 50 minutes of slaughter, Roaran burns about 1100 calories.

    Let’s keep the math easy, and say that our young spartan can go through two men a minute; that’s 2400 calories burned after 1:40 hours of vigorous, nonstop effort.

    This isn’t an impossible feat, per se; the world record for marathon running was set by a guy able to sustain an average speed of 20mph for a little over two hours (that’s over 2000 calories)

    But you have to consider that: 1) spear thrusts will exhaust you faster than long distance running, 2) Marathon runners spend months preparing for their big race, planing how they exercise and what they eat to maximize their performance, and 3) there’s no way that Roran, a medieval farm boy, could be in the same physical condition as a modern athlete.

    In conclusion, Roran is a ridiculous character.

  10. SlyShy on 17 February 2009, 01:51 said:

    Heh, I might have to get you as a collaborator for the next of these. :P

  11. Lucywannabe on 17 February 2009, 10:50 said:

    That’s just plain awesome, and shows just HOW ridiculous a character Eragon actually is.

    Hell, even looking at this from a Dungeons and Dragons perspective, that’s overpowered: the only things in D&D that can lift that much have a Strength score of 30 or so, and beings with ability scores in the 30s are either: 1) Gods or 2) Epic Level non-deities. That’s even on par with the game’s iconic creature, Dragons. And those are things that are NOT common (or, they shouldn’t be, if you’re DM’ing the game right :P), and characters of that level are basically unplayable since nothing presents a challenge to them anymore.

    [Glances at my dragon comment. Glances at Eragon’s world]

    Ohohohoho…now I’m REALLY amused. This must mean that Alagaesia’s dragons are also ridiculously overpowered, since they’d have to be to compensate for the resident Gary Stu.

    (And yes, I’m a girl that plays Dungeons and Dragons on a regular basis. Try not to have a heart-attack like that boy in the hobby store almost did the day I waltzed in with a PHB under my arm)

  12. SubStandardDeviation on 17 February 2009, 13:16 said:

    1) Gods or 2) Epic Level non-deities
    Sounds a lot like Eragon, then.

    Ritual: Deus Ex Machina Ceremony
    Material components: We elves care not for such silly things, mortals
    Casting time: 10 minutes
    Duration: Instantaneous
    Effect: Cure all afflictions. Gain 20 levels in the class(es) of your choice. You have the racial benefits of Humans, Elves, and Half-Elves.

    (And yes, I’m a girl that plays Dungeons and Dragons on a regular basis. Try not to have a heart-attack like that boy in the hobby store almost did the day I waltzed in with a PHB under my arm)
    We have a wonderful thread on the forums for such further anecdotes as you’d care to share.

    What Age Category would Saphira and Thorn fall under, I wonder?

  13. SlyShy on 17 February 2009, 13:30 said:

    If we were going off of DnD rules, they’d still be wrymlings, but based off power levels, they have to be young adults by now.

  14. Nate Winchester on 17 February 2009, 15:25 said:

    We’ll want to account for the force of friction here, and we’ll assume the grass isn’t already slick with blood, in which case mu = .35 should serve as a reasonable guide.

    Funny, when I read the scene I pictured the guy as being lifted up and propelled through the air with the force of the blow (you know, what should have happened). If we account for only wind resistance, what’s the calculations? (biology, not physics nerd)

    Artimaeus, don’t forget that those athletes eat a LOT and probably have more body fat than Roran should have. Especially if he’s a POOR farm boy then he should be rather calorie starved.

    Just for fun, I tried out this calorie calculator here. I put Roran at 19 years old, 160 lbs, and a generous 6 feet tall. (accounting for his Stuness, if we were being accurate, he should be shorter) Also cranked it up to their max: “Daily exercise + physical job”.

    Results?

    To maintain his current body (which he probably does, obesity is NOT a problem with primative poor), he’d have to eat 3383 calories per day. 2706 calories to lose fat and 2030 for extreme fat loss. The man would have to eat 42.2g of protein and 63.3g of carbs every meal. We’re talking about 2 good sized steaks every meal.

  15. SlyShy on 17 February 2009, 16:49 said:

    You know, Eragon’s punch was probably even stronger. I didn’t account for the energy absorbed by the soldier’s lung collapsing…

  16. Naiviv on 17 February 2009, 17:34 said:

    F(punch) for Eragon made me think of Falcon Punch. Perhaps it would be plausible if Eragon were Captain Falcon? Indeed, Cap can launch people at least fifty feet into the air (if SSB scales are accurate). =D

    By the by, how do you insert subscripts?

  17. Tiefling on 17 February 2009, 17:42 said:

    yet another girl who plays DnD regularly (as can be guessed by my nom du crime…er plume) and I gotta say I’ve been suspecting that good ole Paolini plays DnD, or is very familiar with the rules because he’s had Eragon drop all kinds of epic level killage over the course of Brisingr (in particular) which explains why his fight sequences have a very shaky grasp of physics and anatomy but a huge appreciation for…er…fists of fury, plus cat’s grace and some improved uncanny dodges. and naturally a loaded die. scowls at Arya’s little killer ballet in the same battle as deconstructed here. What the Hell was up with her jumping from horse to horse killing with her *knees?!

  18. Rand on 17 February 2009, 19:04 said:

    This is so complicated.

  19. SlyShy on 17 February 2009, 19:12 said:

    Naiviv,

    You can use the html tags <sub></sub> or using Textile you can surround the subtext with ~.

    Tiefling,

    Yeah, and Brisingr is just a flameburst +2 brightsteel sword.

    Also… so many girls that play DnD. When did this place become such a repository of awesome?

  20. Nate Winchester on 17 February 2009, 19:55 said:

    I still don’t believe ‘em, SlyShy. I think we should demand them post pics of them rolling some d20s.

    Maybe that could be another II fund raiser. “Gals of D&D” calendar.

  21. SlyShy on 17 February 2009, 19:59 said:

    As much as that idea amuses me, I can already hear the “NO“s. :P

  22. Nate Winchester on 17 February 2009, 20:03 said:

    Oh c’mon SS, you know the girls around here are putty in your hands. Imagine a scene with dice and an impishidea t-shirt…

    It’s a license to print money.

  23. SlyShy on 17 February 2009, 20:18 said:

    I suspect I hold less sway than you think I do. The girls here are a feisty lot—otherwise they’d be reading Twilight and enjoying the submissiveness. :P

  24. Nate Winchester on 17 February 2009, 20:23 said:

    And that’s why we love them isn’t it?

  25. Rand on 17 February 2009, 20:34 said:

    Feisty people can fall for the dumbest things. It’s practically in their nature.

  26. Apep on 17 February 2009, 20:36 said:

    Let’s face it, there’s nothing sexier than a smart woman. For proof, I recomend Ernest Cline’s “Nerd Pron Auteur”.

  27. SlyShy on 17 February 2009, 20:46 said:

    the girls around here are putty in your hands

    For the record, the vice versa of this statement is far more accurate.

    Apep,

    They are my weakness. >_>

  28. LiquidNitrogen on 17 February 2009, 21:58 said:

    About the calorie count, Roran should be using up even more calories that projected; we forget to factor in blood loss, shock, the energy required to keep balance on a slick surface, et cetera. Also, Roran gets his left deltoid slashed about three quarters of the way through the battle.

  29. Nate Winchester on 17 February 2009, 22:23 said:

    “Hey Sly, how many calories does Roran need?”
    “Over 9,000!!!!”

  30. scary_viking on 17 February 2009, 22:35 said:

    It’s not so much about calorie use where it trips up, seriously. It IS silly in that regard, but that is FAR from the biggest issue. More like, killing 193 men while taking enough wounds to kill quite a few. I mean, Paolini counts minor broken bones and dagger cuts as MINOR WOUNDS, and says that the guy recieved SEVERAL DOZEN. Throw an impaled shoulder and calf on top of that, and you have an amazing performance from a random viking that popped out of nowhere Roran.

  31. Nate Winchester on 17 February 2009, 23:51 said:

    Clearly Paolini has drawn his research from Die Hard.

  32. Legion on 19 February 2009, 13:07 said:

    This is one of those scenes where it’s clear that CP didn’t do any research at all. I laughed when I read about Eragon, a “trained and experienced,” fighter punching someone in platemail with his fist.

    Anyone who’s done research on empty handed fighting (or taken any sort of martial arts classes) knows that you don’t use a flat fist to hit hard (or hardened) areas of the body. First of all, it’s a hard surface vs a hard surface and you do just as much damage to yourself as the opponent, if not more. Second, in a flat fisted punch your skeletal structure is stacked incorrectly to take the energy transferred back (think billard ball hitting a billard ball) and you’d end up breaking all the bones in the back of your hand because of the recoil. It’s a stupid way to fight for a “trained and experienced” warrior. The proper way to strike would have been with pushing, not punching, using an open palm (soft to hard) or a stright thrust-kick with the flat of the foot.

    Looking at Sly’s calculations, I bet that an impact of bone to metal using the amount of force above would have ended up shattering his hand and forearm, maybe even dislocated Eragon’s shoulder rather than actually send the opponent flying any significant distance. It’s like ramming a golf cart into a concrete wall at high speeds. The cart crunch and crumple in on itself as it hits then bounce back before the wall will go anywhere.

  33. SlyShy on 19 February 2009, 13:56 said:

    To be fair, he actually does break his hand. Except then he uses magic to make everything better again.

  34. Legion on 19 February 2009, 15:19 said:

    Yes, I’ll give CP that concession, even though the injury to Eragon should have been much worse than actually described considering the amount of force used. But really, Eragon injury as a result makes this entire scene even more ridiculous.

    Inconsistency #1 – As mentioned in your article above.

    Inconsistency #2 – CP is nonstop demonstrating how amazing and capable a warrior Eragon is since page 1 of Brisingr, then he goes and writes something like Eragon using a barehanded fist to punch a guy’s plate armored chest. That’s not something a smart fighter would do. Hell, even a 10 year old white belt knows that’s a no-no.

    Inconsistency #3 – Let’s say that Eragon is the Dragon Rider so he fights like someone who has an adamantium skeleton and healing factor. He doesn’t need to worry about fighting smart because his Dragon Rider status pwns everyone. That’s the attitude CP has Eragon take going into the fight. BUT, lo and behold, when he fights recklessly like a superhuman Dragon Rider he gets himself injured. It’s like CP has Eragon be godlike for the first half the scene, then human again for the second half. If CP was being consistent, Eragon would have either used smart fighting tactics from beginning to end or not be injured at all. It’s another one of those superficial weaknesses artifically given to godlike Eragon. CP has Eragon be a Dragon Rider superhuman when the plot calls for it then human again when the plot calls for it. The entire outcome of this scene only makes sense as a plot device and nothing else. Eragon’s Falcon punch and broken hand was thrown in there without thought by CP for the sole purpose of having Arya and Eragon share a moment afterwards.

    Anyways, I’m really glad you started this series, and I look forward to the next installment because more than anything else, it shows that CP can’t manage internal consistency even using his own version of physics.

  35. Tiwar Sauil on 19 February 2009, 15:51 said:

    Hasn’t CP stated that magic requires as much energy as doing something normally would?

    How much energy does it take to heal a broken hand? Anyone know?

    Does he not have any backup weapons, either? No handy knife for stabbing people he is grappling? what about, you know, strangling him to death? Isn’t that a bit more sensible than punching somebody flying, if you are trapped? (I know there are techniques in real martial arts for punching at close range, but still)

    I could go on, but you get the idea.

  36. SlyShy on 19 February 2009, 16:40 said:

    Does he not have any backup weapons, either? No handy knife for stabbing people he is grappling? what about, you know, strangling him to death? Isn’t that a bit more sensible than punching somebody flying, if you are trapped? (I know there are techniques in real martial arts for punching at close range, but still)

    He was snapping necks up till now.

    What I find is ridiculous is that Eragon decides he likes Falcon Punching people to death, so he tries to figure out a way to do it without breaking his hand. His solution is to grow a layer of callous over his knuckles. This, apparently, is enough protection to prevent future injuries. Which is not how it works in the real world, okay.

  37. Tiwar Sauil on 19 February 2009, 16:50 said:

    Why can’t he snap the neck of this guy then?

    I’m sure the dwarves, with their ability

    Ignore Biology(Ex)
    Due to their strange customs, dwarves have the ability to completely ignore the biology of creatures if this would allow them to do something that the DM deems to be “cool”.

    Could make replace his bones with giant steel pistons of something.

  38. Legion on 19 February 2009, 16:53 said:

    Haha, that too. Talk about not doing any research whatsoever on even the most basic principles of empty handed combat. Smooooooooth, CP, real smooth. You need to lay off the HK kung fu movies, dude.

  39. SubStandardDeviation on 19 February 2009, 17:20 said:

    I personally pictured him screaming a war cry and blasting the guy back with ki like in DBZ, myself.

    Maybe that could be another II fund raiser. “Gals of D&D” calendar.
    Great idea! We can have the number of the month correspond to her Charisma score! (No offense to any D&D player her who considers herself ‘hot’)

    Talk about not doing any research whatsoever on even the most basic principles of empty handed combat.
    Of course not! Don’t you know CP makes his own swords? Because sword fighting is so much cooler!

    Just for fun, let’s count the number of things Eragon is proficient in by now:

    • Bow/arrow
    • Bastard sword
    • Ride
    • Arcane magic (Abjuration, Conjuration/Healing, Divination, Evocation, at least)
    • Perform (oratory)
    • Heavy armor
    • Some sort of shield
    • Quarterstaff
    • Unarmed combat

    He also has ridiculously high saves and CHA, though his INT and WIS are quite lacking.

  40. Legion on 19 February 2009, 17:32 said:

    OMG. I’m totally going to hack a Neverwinter Nights 2 character based on the stats above.

    Then I shall post screencaps. >=]

  41. SlyShy on 19 February 2009, 17:35 said:

    Maybe that could be another II fund raiser. “Gals of D&D” calendar.
    Great idea! We can have the number of the month correspond to her Charisma score! (No offense to any D&D player her who considers herself ‘hot’)

    I did a spit take, hahaha.

  42. Tiefling on 19 February 2009, 19:02 said:

    okay OT I know, but I would totally do a Gals of DnD gig, along with the…5 other chicks I game with.

    When are more physics articles coming out? Not that I can make sense of them, I just like the idea that someone could potentially mail all of the proofs to Paolini and say “DUDE, read a freaking textbook!!!” I find that level of…ignorance is a polite word…maddening

  43. SlyShy on 19 February 2009, 19:12 said:

    okay OT I know, but I would totally do a Gals of DnD gig, along with the…5 other chicks I game with.

    Okay… now this is starting to sound too good to be true. I think we all know the phrase that applies now. :P

    When are more physics articles coming out? Not that I can make sense of them, I just like the idea that someone could potentially mail all of the proofs to Paolini and say “DUDE, read a freaking textbook!!!” I find that level of…ignorance is a polite word…maddening

    Potentially very soon. I’m a bit busy with some philosophy papers, but beyond that I might be free-ish this weekend.

  44. Tiefling on 19 February 2009, 19:58 said:

    OT again but ‘tis true, I know 5 women who game regularly. If it helps, it’s because I’m part of both the GBLT and BDSM community,where role-playing takes on new and exciting meanings.

    perhaps you could combine philosophy and physics to get the Metaphysics of Alagaesia? (boy do I hate spelling that word)

  45. SlyShy on 19 February 2009, 21:14 said:

    The metaphysics are pretty messy too. It’s been a long standing project of mine to try and sort through his magic system, but right now I don’t have the patience to re-read each of the books to mine for information. I might have to attempt that this summer, or delegate it to someone more capable.

  46. ExitMouse on 20 February 2009, 04:16 said:

    Huh…a gigantic time-sink that demands reading through >1500 pages scanning for small details to assemble a system of rules and find internal inconsistencies…

    It’s perfect!

  47. SlyShy on 20 February 2009, 04:23 said:

    Awesome, a more capable person!

  48. Nate Winchester on 20 February 2009, 09:34 said:

    I think this is where I tell SlyShy: “I told you so.”

    (No offense to any D&D player her who considers herself ‘hot’)
    Silly SubStandard, we just list those girls as having used charisma as a “dump stat”.

    Semi-OT: every time I hear someone say they like smarts in a mate, I imagine a pin-up calendar of brains.

    P.S. SlyShy, what’s the textile shortcut for blockquoting? It’s not on the help.

  49. SlyShy on 20 February 2009, 11:06 said:

    “bq.”

    Proceeding the text you wish to quote. Yeah, I should add that to the help, I realize.

  50. Virgil on 20 February 2009, 21:53 said:

    Needless to say, my jaw dropped when I saw 7500 Newtons.. also, love Fpunch.

  51. The Angel Islington on 20 February 2009, 22:10 said:

    What is 7500 Newtons equivalent to, just for scale?

  52. SlyShy on 20 February 2009, 22:37 said:

    It’s pretty hard to express it in a way that is illustrative, because 7500 Newtons is a force, and we don’t typically encounter forces in our everyday lives.

    A 70kg ~ 150 lb man could do the following with 7500 Newtons, if he spent it all instantly. 7500/70 ~ 107 ~ 100. 0 = 100 – 10t, t = 10.

    h = 10*10 – 1/2 * 10^2 = 50m.

    So, jump 150 ft.

  53. The Angel Islington on 20 February 2009, 23:34 said:

    Wow, that’s ridiculous, even for a fantasy character.

    How would you even accomplish that kind of thing with Pao’s magicks?

  54. CometStorm on 20 February 2009, 23:36 said:

    I think I’ve figured out how Roran sustains himself!

    Before a battle, his lackeys will bring him a sacrifice: a goat, a horse, or even a small slave boy if he’s lucky!

    Then he devours them whole. Nom, nom, nom. :3

    The sacrifice adds to his epic God-ness. His underlings worship him like the God CP wants him to be.

    Haha, I used to play Dungeons and Dragons, when I was in middle school, but there is no one to play with at my school or around where I live anymore!

  55. SubStandardDeviation on 20 February 2009, 23:55 said:

    “bq”(No offense to any D&D player her who considers herself ‘hot’)
    Silly SubStandard, we just list those girls as having used charisma as a “dump stat”.

    Nate, if you see my forum signature, you’ll notice I have a lot of “dump stats.”

    CometStorm, you’re female, right? Join the calendar!

  56. SlyShy on 20 February 2009, 23:58 said:

    Sorry, that was unclear. Remove the quotation marks from “bq. “. :P

    And yes, the more the merrier. As in, 12 is great. ;)

  57. SubStandardDeviation on 21 February 2009, 00:24 said:

    Ah, there we go.
    As in, 12 is great. ;)

    So far Tiefling is six, Lucywannabe and CometStorm are one each, and I’m the Ranger/Shadowdancer with Favored Enemy: Camera. ;)

    I think I’ve figured out how Roran sustains himself! Before a battle, his lackeys will bring him a sacrifice

    Still doesn’t explain how a vegan like Eragon can have super strength. Or any of the Elves, for that matter.

  58. CometStorm on 21 February 2009, 00:26 said:

    Yeah, I’m a girl.

    Calendar, say what?

    Haha, I’m so tired most of the conversation kind of rolled right past me.

    Now that I think about it, Roran has to eat like Micheal Phelps on the munchies.

    My friend, who’s a swimmer, says that MPhelps eats like 2,000 calories for breakfast alone, so I guess it can be done.

  59. CometStorm on 21 February 2009, 00:29 said:

    Still doesn’t explain how a vegan like Eragon can have super strength. Or any of the Elves, for that matter.

    They sacrifice the Ents instead?

    ((Sorry for the double post, I didn’t see SSD’s comment)

  60. Bibliocurious on 21 February 2009, 04:02 said:

    I’ve been checking this site for a while, but never posted. What a topic to inaugurate myself with.
    As someone living with a waterpolo player, I know firsthand how much one person needs to eat to maintain muscle mass, especially a young man.
    So, Point A). Roran is a farm boy. Although he is a poor farmboy, farming and working in a forge is extremely hard exercise. CP said he’s very buff at the beginning of Brisingr, so if he’s 6 feet (highly unlikely in a medieval setting, no nutrition meant they averaged about 5’6”) he must weigh about 175-200 pounds.
    Point B). Even though he no longer is farming nor forging, Roran is doing various soldierly activities like going on patrols and doing drills (if memory serves). He generally stays very active, so we can reasonably assume that he manages to stay fit at his farmboy levels.
    Point C). He needs to maintain that muscle mass through food. The Varden camp, we read in Brisingr, is well-equipped to deal with feeding armies. I mean, Saphira eats a whole cow and no one really blinks. Hardly a hard-knock rebellion, but whatever. So, as Eragon’s cousin, he probably gets more than his fair share and eat all he wants. Roran probably consumes about 6,000 calories a day, half of what Michael Phelps eats and an amount frequently consumed by any male doing hard physical exercise every single day.
    And, consuming 6,000 calories a day is not that hard to do. That’s two or three loaves of bread, a steak or two, lots of fruit and vegetables, especially potatos, corn, rice, etc. Just one bowl of pasta is about 800 calories.

    oh and Point D). Explained in layman’s terms because I’m too lazy to look all of this up right now. Roran’s wounds probably wouldn’t affect him that much because in those types of situations, the adrenaline rush + panic sort of “shuts down” your reactions to or even awareness of pain and/or injury.

    …Please, please, please tell me I didn’t spend 10 minutes writing a dietary guide on a character from Inheritance.

  61. SlyShy on 21 February 2009, 05:04 said:

    The main issue is how long the fight lasted. It’s quite possible for adrenaline to carry you through pain, but only for a certain while, after which you crash hard. Roran certainly takes his sweet time.

  62. scary_viking on 21 February 2009, 16:43 said:

    Not to mention, carrying yourself through pain only goes so far. There’s still blooc loss to consider. Being impaled through the calf alone is enough to put anyone out of combat immediately. Even ignoring the issue of pain, that’s still 1 leg that can’t be used effectively and a huge drain of blood and energy which would probably result in death if not treated immediately. And yet, that is one amongst dozens of wounds he takes during the 193-man battle.

    Even if you don’t feel pain, there is a point, and it doesn’t take all that much to arrive at, where limbs simply refuse to respond to prompting. Some people ie Paolini. This is why people who go nearly all-out in the 100-yard backstroke may have to pace themselves quite slower in the 200-yard backstroke. It has nothing to do with pain. It has everything to do with limbs not responding fully after 100 yards or so.

    Inheritence suggests that performance is entirely based on willpower. Which is a hugely common ideal, but one which anyone who has ever paid any attention to anything knows is a load of bullshlapskie.

  63. scary_viking on 21 February 2009, 16:44 said:

    Sorry for double post, I have no idea where that ‘Some people ie Paolini’ phrase got in there O.o
    Maybe I was writing a sentence, stopped, and forgot to come back, lol.

    x.x, I am full of fail.

  64. Addie on 21 February 2009, 23:07 said:

    lol, I was wondering about that. Thanks for explaining. :)

    Inheritence suggests that performance is entirely based on willpower. Which is a hugely common ideal, but one which anyone who has ever paid any attention to anything knows is a load of bullshlapskie.

    Not entirely. Willpower does help an awful lot.

    But on the other hand, point taken: you need to condition and pace yourself properly, too.

    You need both willpower and proper pacing – determination, and proper tactics.

    Yeah, you’ve got to have it all. ;)

  65. Shaleen on 22 February 2009, 16:39 said:

    Mmmmm physics is sexy.
    Well done.

  66. Gray Falcon on 23 February 2009, 12:49 said:

    Good physics. Of course, one also wonders why a punch with that much force didn’t knock Eragon down.

    My problem with the punch was that it was out of setting. In a superheroic setting, that kind of thing would go unnoticed. If Monkey D. Luffy of One Piece sent someone tumbling a dozen feet, the reaction would be “Luffy must be tired”.

    Interestingly (but par for the course for a shonen series), Luffy can also be left exhausted after a major battle, sometimes sleeping for days. Afterwords, he can tell how long he was out by determining how many meals he missed, at five a day.

    Nobody’s expected to take One Piece seriously. This works because it’s funny.

  67. Optimus on 25 February 2009, 22:24 said:

    I’m going to give Paolini the benefit of the doubt here and assume that he meant that the guy flew through the air, as opposed to sliding across the grass. In this case, we’re dealing with projectile motion.

    Assuming that Eragon were to lift the 100 kg soldier at a perfect 45 degree angle and there is minimal air resistance, he would need to throw the guy at approximately 6.25 m/s in order for him to fly 4 meters horizontally.

    With SlyShy’s .1 second estimate for the time of collision, the applied force comes out to 6250 N. Which means that Eragon could only bench press 1460 lbs. with one arm. So you see, it’s all perfectly logical. Haha.

    Sorry for being a dick, I was bored.

  68. SlyShy on 25 February 2009, 22:35 said:

    The reason I assumed he was sliding was because he tripped over a dead man as he was being pushed back, which means his legs had to be low enough to trip him up. But yeah, it ends up being ridiculous almost any way you run the calculations.

  69. Optimus on 25 February 2009, 22:43 said:

    Kind of makes you wonder if Paolini has researched anything he throws in these books.

    From a biologically standpoint, would a fountain of blood really spurt out of his chest? The force of the impact is going into the guy, not to mention through a thick sheet of armor, so unless I’m missing something here, I don’t see how “a fount of blood” could possibly “erupt” from his chest.

  70. SlyShy on 27 February 2009, 06:36 said:

    He was probably inspired by Mortal Kombat, or something. Maybe video games have some effect on children; they make children write worse bad escapist fantasy novels.

  71. scary_viking on 28 February 2009, 20:45 said:

    Hmm. I did some calculations assuming a completely elastic collision, a 75kg man/equipment combo which needs to fall completely on his chest which I’m assuming to be 1.5m off the ground before he is considered to have hit the ground, only 12 feet even though Paolini says it’s more, and an impulse time of an entire .2 seconds.
    So I’m pretty much using low-bound easy going values to try to solve for the guy ‘flying’ through the air 12 feet.

    Anyhow, for a .2 second punch, I figured 2711N of force. For Sly’s .1 second punch, it comes to 5422N of force.

    Did I mention that the KE change would be about 3920 J (about 2893 foot pounds).

    When compensating for all that talk about how blood spurted everywhere (aka, energy being dispersed EVERYWHERE), it’s likely that the punch was more powerful.

    If it isn’t obvious, 2893 foot pounds is the amount of work needed to lift 2893 pounds 1 foot. For that to be the KE change in the punch direction after the dispersion of energy is accounted for…

    Holy ****.

  72. Fenix on 3 March 2009, 09:57 said:

    Bad, bad physics, the “quadratic formula” you used(or at least I think this is the one, I’m unfamiliar with English math jargon) is -b+-sqrt(b^2-4ac0/2a

    where abc are given by ax^2+bx+c, you used time for x, so V0 should be dependant on t as in V0=sqrt(t)(or maybe something like 0.5dt/dx). Since this isn’t the case you calculation is bogus.

    I’m going to think about the problem and see if I can find a solution, also please correct me if I’m wrong and I misunderstood your equation.

  73. Fenix on 3 March 2009, 10:47 said:

    K, I made a mistake, your t’s and +‘s are written the same way, so I missed the t in your equation and my above commentary becomes invalid.

    I still believe there’s something fishy going on though, it somehow strikes me as wrong that t can be either 1 s or 1.14 s. But even after I checked your calculations I couldn’t find it.

  74. SlyShy on 3 March 2009, 23:44 said:

    My bad. As a mathematics major, I really should work on my handwriting. It used to be, I curled by T’s, so it worked out fine.

  75. Fenix on 4 March 2009, 12:11 said:

    I gave the issue some more thought, you used v=v0+at and s=v*t thus s=(v0+at)t=v0t+at^2, quadratic formula to “solve” v0.

    This however gives two possible values for t, that can’t be right, so I’m going to try something different.

    we know the acceleration is -3.4m/s^2
    we don’t know v0, but we know that if s=4 then v=0 and that v=a*t+v0
    thus we know v=a*t+v0=0 at some value of t.
    lets say that’s at te, then v(te)=a*te+v0=0
    so te=(-v0/a)

    s(4)=v(average)*te=((v0+v(te))/2)*te=((v0+0)/2)*te=-v0^2/2a=4—>-v0^2=8a
    a=-3.4—>v0^2=27.7
    v0=sqrt(27.7)=5.22 m/s

    In order to verify the results I’m going to do a “reversed” check. if an object get launched away with an a of 3.4 m/s^2 what is it’s speed after 4 meter?
    potential energy is m*s*a
    kinetic energy is 0.5mv^2
    Ek=Ep—> 0.5v^2=s*a —> v^2=2sa s=4 v^2=8a
    That gives the same answer as above.
    The time it took for the object to fly is now 5.22/3.4=1.54 s

    Does that make sense to you?

  76. SlyShy on 10 March 2009, 01:58 said:

    You, sir, are completely correct. Most assuredly, you are a gentleman and a scholar.

  77. Aldrea945 on 4 December 2009, 16:26 said:

    I know I’m late on this, but…

    Me: Stares blankly. Huh?

    Bella: Reads it. Head explodes.

    Me: Ew.

    Edward: Walks up. NOOOOOOOOO!!! You did this!!!! You- Shoots him in the head and pushes him off a cliff.

    Me: Die already!

    Edward: Faintly, NEVER!

    Eragon: Walks up. Who’s that?

    Me: Your new love interest. Shoots him in the head and pushes him off the cliff. A large boom is heard.

    Arya: Where’d the stalkers go?

    Me: You ate them.

    Arya: NOOOOOOOOO!!!!!! Wait, what?

    Me: Pushes her off the cliff.

    Arya: I forgot my parachuuuuuuuuuutttteee. Boom.

    Me: Looks over the side. Dead yet?

    Them: NOOOOO!

    Me: Dang. Throws a random bomb in. Boom. Walks away.

  78. The Cat on 26 February 2011, 18:12 said:

    HAHA! Brilliance! I hadn’t seen this article yet, but for the sheer destruction of any realism in Inheritance, this one completely nails it.

    Can’t wait for more of these.

  79. ack4 on 4 June 2012, 17:11 said:

    Very funny, I also have been thinking about the physics of Alagaesia a lot. However, I found faults with your reasoning; firstly, the text suggests that the soldier went through the air, as opposed to sliding across the ground. Secondly, punches are NOT mere feats of strength, but also take advantage of the momentum build up in the whole body. Finally, he could have been using magic as he preformed the punch.

  80. Tim on 5 June 2012, 10:03 said:

    firstly, the text suggests that the soldier went through the air, as opposed to sliding across the ground.

    It suggests he struck the guy straight on in the middle of the ribcage. It says “over the grass” rather than “into the air.” It really doesn’t matter since this is still impossible.

    Secondly, punches are NOT mere feats of strength, but also take advantage of the momentum build up in the whole body.

    It’s represented as him quickly lashing out as hard as he can, not as a big haymaker with a windup. Regardless, the laws of motion say that if he hits a man hard enough to destroy his ribcage and throw him a dozen feet backwards, he subjects the bones in his arm to enough force to shatter a man’s ribcage and throw him a dozen feet backwards. The human wrist is not tougher than the human ribcage and certainly isn’t tougher than plate mail. Even if Eragon was this strong he should have destroyed his entire arm in the process of throwing this punch.

    Finally, he could have been using magic as he preformed the punch.

    Except it says he struck him with all his might, not mentioning magic at all. And he’d have had to have said a magic word if that were the case, which it doesn’t mention either.

  81. Tim on 5 June 2012, 10:48 said:

    As an addition, the F punch number here is actually way too low because it doesn’t include the work done doing mechanical damage to the soldier’s body rather than throwing him backwards. The transfer of forces shown here is basically impossible since Eragon apparently destroyed the guy’s mail, his sternum (the fount of blood implies he broke the armour rather than just denting it to the point of shattering his ribs), then transferred enough force to him to throw him backwards even though the only thing for his fist to act on was the contents of the guy’s chest cavity (unless he hit him so hard he ended up punching the front of his spinal column). What should have happened, given the forces involved and the apparent ludicrous strengh of Eragon’s arm bones, is Eragon putting his fist right through the guy and the guy not going anywhere.

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