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Lord of the Rings Physics Homework

Posted August 14, 2014 12:29 PM

From WIRED:

How Long is the Balrog's Whip? Here's the scene. Gandalf and the rest of the party are trying to escape from Moria. They cross a narrow bridge and then Gandalf makes a stand agains the Balrog. In order to prevent the Balrog from crossing, Gandalf breaks the bridge and the monster falls. But wait! At the last second, the Balrog's whip grabs a hold of Gandalf and pulls him into the chasm. Let's get data from the video to estimate the length of the Balrog's whip.

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#1

Re: Lord of the Rings Physics Homework

08/14/2014 2:45 PM

You do realize this is fiction...?

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#3
In reply to #1

Re: Lord of the Rings Physics Homework

08/14/2014 3:29 PM

An attempt to make Physics more fun. The Wired posts on the math behind the Star Wars Death star and Avengers movie arrow shot was rather interesting.

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#4
In reply to #3

Re: Lord of the Rings Physics Homework

08/14/2014 3:45 PM

"An attempt to make Physics more fun."

Make physics more fun? But it's supposed to be a dry and humourless pursuit, full of those silly rule sticks with that slidey thing and pipe smoking men in rumpled short-sleeve shirts and ties with pocket protectors jammed full of things...

Oh, wait... what room is this? I'm looking for Worn Stereotypes, room CR3.

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#7
In reply to #3

Re: Lord of the Rings Physics Homework

08/14/2014 6:27 PM

Physics already is more fun!

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#2

Re: Lord of the Rings Physics Homework

08/14/2014 3:26 PM

Like many anonymous posters asking homework questions here on CR4.....

"YOU SHALL NOT PASS !!!!!"

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#5

Re: Lord of the Rings Physics Homework

08/14/2014 4:41 PM

I think his reasoning is flawed. As I recall, at least part of the plunge into the depths was shown in slow motion. So his 13.8 seconds is too long. If it was shot at a nominal 60 fps and played back at a typical 24 fps, his time could be too long by a factor of up to 60/24 = 2.5; so the duration of the fall for the whip to entangle Gandalf could have been as brief as 5.52 seconds.

(What is this word 'fiction' people keep using?)

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#6

Re: Lord of the Rings Physics Homework

08/14/2014 5:33 PM

Personally I found 'Gone in 60 seconds' to be far more of a reality bender than Lord of the Rings.

At least in Gandalf's world there really could be unexplainable magic allowing for such actions and items to exist.

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#8
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Re: Lord of the Rings Physics Homework

08/14/2014 11:31 PM

It was a magic whip that could get as long as the owner wanted it to. On the other hand, I would guess 4 foot 2 inches.

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#9

Re: Lord of the Rings Physics Homework

08/14/2014 11:36 PM

The length of Balrog's whip is just a another fun problem/Amessage. I had a somewhat similar problem regarding Lois Lane falling from a building and Superman's Initial velocity to rescue her before she hit the pavement. This was in 1960. Physics profs never change, just their characters.

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#10
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Re: Lord of the Rings Physics Homework

08/15/2014 12:06 AM

Wow, interesting problem. Sudden stops tend to be difficult on the human body, regardless of whether it is due to concrete or Men of Steel. The interesting question is how high above the pavement Superman would have to catch her in order to avoid lethal G forces, using different catch techniques. Falling into his arms in standard damsel-in-distress position just above the pavement would seem to be among the worst. Catching her in his super cloak might be better. I think he should use his super breath to cushion her fall evenly across her body. Of course, super breath has its own problems. He can only blow out a single lungful of air. No matter how forcefully he may try to inhale, he has to depend on ordinary air pressure to push air into his lungs. Then he can exhale it as forcefully as he wants.

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#11

Re: Lord of the Rings Physics Homework

08/15/2014 12:19 AM

The Balrog is made of fire. So even if having wings, being a demon, and being magical don't affect his rate of fall, being made of flame might affect his buoyancy. Also, maybe he was fleeing instead of falling.

Fundamentally, he will fall as fast as the director wants him to fall. The whip is as long as the director wants it to be. The only way to determine those numbers is to measure it. Someone may be able to use the video clip to see how fast he shrinks, and let go of assumptions of the acceleration of gravity and air resistance.

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#12

Re: Lord of the Rings Physics Homework

08/15/2014 2:37 AM

Who could ever vote #2 OT? That was one of the best answers of all time!

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#27
In reply to #12

Re: Lord of the Rings Physics Homework

08/17/2014 3:27 PM

Perhaps they didn't understand my meaning in post #2, in that case I say to them.....

"YOU SHALL NOT PARSE !!!!!"

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#28
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Re: Lord of the Rings Physics Homework

08/17/2014 3:37 PM

Maybe they just have to see the movie.

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#29
In reply to #28

Re: Lord of the Rings Physics Homework

08/17/2014 3:56 PM

For kids today with their shorter attention spans watching the extended directors-cut version of the Lord of the Rings movies IS classified as undertaking an epic journey.

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#31
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Re: Lord of the Rings Physics Homework

08/18/2014 2:56 AM

Your #2 was a delight! Thanks for the moment..

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#32
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Re: Lord of the Rings Physics Homework

08/18/2014 3:11 PM
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#13

Re: Lord of the Rings Physics Homework

08/15/2014 2:42 AM

In the world of fantasy, it's always long enough.....

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#14

Re: Lord of the Rings Physics Homework

08/15/2014 3:41 AM

The whole damn point is..

Physics is fun when applied to a REAL situation where it will add some sort of value to the job, project, situation.

Who gives a f*uck how long Balrog's tadger is?

Del

(Just in case it isn't apparent I'm in grumpy mode)

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#15
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Re: Lord of the Rings Physics Homework

08/15/2014 4:59 AM

Balcat cares.

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#16
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Re: Lord of the Rings Physics Homework

08/15/2014 5:54 AM

Ooooooh scarey cat
Del

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#18
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Re: Lord of the Rings Physics Homework

08/15/2014 10:31 AM

But he's magnificent in his scariness!

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#19
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Re: Lord of the Rings Physics Homework

08/15/2014 1:56 PM

Here's a real situation:

In 1975 my friends and I were out in the Mojave Desert exploring when we came across what looked like a large pipe sticking about 15 cm out of the ground. As it was in the middle of nowhere we thought it might have been an abandoned well or something. It went straight down as far as we could tell.

I shined a torch down the pipe and could see a tiny dot of reflected light at the bottom, probably water. We wanted some idea how deep it was and so we did what anybody would do: we dropped rocks down the pipe to see how long it took them to hit bottom. It took an awfully long time! In fact, we'd dropped several rocks before hearing the first, thinking we'd missed it. Then we heard it followed by the sounds of the others hitting bottom in the same pattern as we'd dropped them. That hole was deep!

As my watch had a chronometer function we dropped a bunch of rocks, timed each one and then took an average: if I recall correctly it was about 14.1 seconds. We chose rocks all having about the same size and shape to keep things as consistent as possible. The rocks were roughly spherical and about 5 cm in diameter.

How deep was the well?

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#20
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Re: Lord of the Rings Physics Homework

08/15/2014 2:17 PM

1/2 x 32 x 14.1^2 feet

Del

That's about 3000'

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#21
In reply to #19

Re: Lord of the Rings Physics Homework

08/15/2014 2:29 PM

3198 feet by calculation, but the delay time for the sound to come back creates an error. Subtract about 2.5 for seconds from the original time 14.1s and redo the calc for a closer estimate of 2100 feet

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#22
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Re: Lord of the Rings Physics Homework

08/15/2014 4:50 PM

less. much less. (why?)

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#23
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Re: Lord of the Rings Physics Homework

08/16/2014 1:11 AM

Terminal velocity.

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#24
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Re: Lord of the Rings Physics Homework

08/16/2014 2:45 AM

We though he said the well was evacuated

Damn Newton monkeying with our brains.. the guy was a damn heretic....
Del

(BTW Great thread hijack by Europium, almost seamless, and what little seam there is could be ground down so it didn't show)

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#25
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Re: Lord of the Rings Physics Homework

08/16/2014 3:22 AM
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#26
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Re: Lord of the Rings Physics Homework

08/16/2014 3:23 AM

Ka-CHING!

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#30
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Re: Lord of the Rings Physics Homework

08/18/2014 2:50 AM

Down boy.........Nothing here to bust a bowstring over!

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#17

Re: Lord of the Rings Physics Homework

08/15/2014 10:18 AM

The only thing that matters in this incident is that Gandolf was an experience point hog.

Instead of everyone participating in the destruction of the Balrog and sharing in the xp, Gandolf had everyone leave while he stayed behind to confront the Balrog. So Gandolf defeats the the Balrog, gets all the experience points and levels up from Grey Wizard to White Wizard.

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