PDA

View Full Version : Santa: Physically Speaking


ReFuSeD!
11/14/04, 09:32 PM
Last year, towards the end of one of my physics leftures, we briefly touched on the thought of Santa delivering presents to all the children in the world overnight. It's all pretty amusing...

Taking a conservative number, there are roughly 2 billion people in the world who are under 18 for Santa to deliver presents to. Ofcourse, Santa doesn't deliver presents to children who don't believe in him (this includes many main religions), which greatly reduced his workload. Taking these numbers into account, Santa has roughly 380 million children to deliver presents to. On average, there is 3.5 children per household, leaving roughly 100 million homes for Santa to visit (assume there is atleast one good child per home). Because of different time zones, Santa has 31 hours to complete his trip which forces him to make around 850 visits per second.

In other words, Santa has 1/1000th of a second to park, hop out of the sleigh, jump down the chimney, fill the stockings, distribute the remaining presents under the tree, eat whatever snacks have been left, get back up the chimney, get back into the sleigh and move on to the next house. Assuming that each househould is evenly distributed around the world (obviously they're not), there is .78 miles between houses. This works out to a total trip of about 78 million miles within 31 hours (also assuming Santa doesn't stop to take a shit and piss after all those cookies and milk). This means that Santa's sleigh is moving at 650 miles per second, 3,000 times the speed of sound. For purposes of comparison, the fastest man-made vehicle on earth, the Ulysses space probe, moves at a pokey 27.4 miles per second - a conventional reindeer can run, tops, 15 miles per hour.

Now consider the huge load in the sleigh! Assuming that each child gets nothing more than a medium-sized lego set (almost 1 kg or 2 pounds), the sleigh is carrying 321,300 tons, not counting Santa, who is invariably described as overweight. On land, non-flying reindeer can pull no more than 300 pounds. Even granting that "flying reindeer" could pull TEN TIMES the normal amount, we cannot do the job with eight, or even nine. We need 214,200 reindeer. This increases the payload - not even counting the weight of the sleigh - to 353,430 tons.

353,000 tons travelling at 650 miles per second creates enourmous air resistance - this will heat the reindeer up in the same fashion as spacecrafts re-entering the earth's atmosphere. The lead pair of reindeer will absorb 14.3 QUINTILLION joules of energy. Per second. Each. In short, they will burst into flames almost instantaneously, exposing the reindeer behind them, and create deafening sonic booms in their wake. The entire reindeer team will be vaporized within 4.26 thousandths of a second. Santa, meanwhile, will be subjected to centrifugal forces 17,500.06 times greater than gravity. A 250-pound Santa (which seems ludicrously slim) would be pinned to the back of his sleigh by 4,315,015 pounds of force.

If, by some chance, Santa could defy these laws of physics, his speed would be so great that he would leave create a force strong enough to disrupt the rotation of the Earth - causing massive tidal waves strong enough to wipe out much of civilization.

Tanooki Suit
11/14/04, 09:41 PM
I'd just like to point out that there is no such thing as centrifugal force.

venus/bacchus
11/14/04, 09:53 PM
Physics makes a very good point, but how does it account for all the elves living at the North Pole. They'll never disprove that one.

ReFuSeD!
11/14/04, 10:01 PM
I'd just like to point out that there is no such thing as centrifugel force.

You're right, there is no such thing as a centrifugel force. That's why I said centrifugal, in which there is such a thing.

Tanooki Suit
11/14/04, 10:10 PM
You're right, there is no such thing as a centrifugel force. That's why I said centrifugal, in which there is such a thing.
Ooh, so I spelled it wrong. Whoop dee do. There is still no such thing as centrifugal force. All so-called "centrifugal" force is, is normal force with a different name.

ReFuSeD!
11/14/04, 10:23 PM
The centripetal force, the action, is balanced by a reaction force, the centrifugal (“center-fleeing”) force. The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force. The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path. Thus, in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path. The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton's first law. If there were in fact a force acting to force the body out of its circular path, its path when released would not be the straight tangential course that is always observed.

venus/bacchus
11/14/04, 10:28 PM
You're right, there is no such thing as a centrifugel force. That's why I said centrifugal, in which there is such a thing.
I hate to say it, but he is right. There is no such thing as centrifugal force in the real world sense. It's known as a "fictitious force" because it can only be explained or applied in rotating references, not in any inertial frame. It's not even an actual push or pull either, so nothing is actually applying it. It's just a by-product of a direction change; meaning it's just inertia displaying itself.

Tanooki Suit
11/14/04, 11:07 PM
The centripetal force, the action, is balanced by a reaction force, the centrifugal (“center-fleeing”) force. The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force. The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path. Thus, in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path. The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton's first law. If there were in fact a force acting to force the body out of its circular path, its path when released would not be the straight tangential course that is always observed.
So you're saying you don't know the definition of normal force then, right?

Mad Caddie
11/15/04, 12:13 AM
Wow, its nice to finally see some intelligent discussion in these forums. as long as no flame wars start, this is a good thing.

Also, that santa thing was a very good read, fictitious forces or not. I had a chuckle.

oreo_emokid89
11/15/04, 04:30 AM
lol that was hillarious
i'm gonna have to tell some little kid that if santa existed his reindeer would burst into flame, and he would disrupt earth rotation

Mercy Medical
11/15/04, 06:36 AM
So are you trying to tell me that Santa isn't real?

Hilikus
11/15/04, 05:14 PM
thats awsome.

SC0926
11/15/04, 05:32 PM
thats awsome.
my thoughts exactly.

No Control
11/15/04, 05:44 PM
I actually found the first post interesting. Though I do think its alright for kids to believe in Santa, gives a mistical feeling on Christmas for a really young kid. But the science of it was really interesting. Good stuff.

aolsux
11/15/04, 07:10 PM
So are you trying to tell me that Santa isn't real?
WHAT?!?! SANTA, NOT BEING REAL, Say it isn't so...say it isn't so...

mondeoman
11/15/04, 07:39 PM
My Physics teacher last year shared this with us. It was amusing.

ohlookitspaul
11/15/04, 08:18 PM
The centripetal force, the action, is balanced by a reaction force, the centrifugal (“center-fleeing”) force. The two forces are equal in magnitude and opposite in direction. The centrifugal force does not act on the body in motion; the only force acting on the body in motion is the centripetal force. The centrifugal force acts on the source of the centripetal force to displace it radially from the center of the path. Thus, in twirling a mass on a string, the centripetal force transmitted by the string pulls in on the mass to keep it in its circular path, while the centrifugal force transmitted by the string pulls outward on its point of attachment at the center of the path. The centrifugal force is often mistakenly thought to cause a body to fly out of its circular path when it is released; rather, it is the removal of the centripetal force that allows the body to travel in a straight line as required by Newton's first law. If there were in fact a force acting to force the body out of its circular path, its path when released would not be the straight tangential course that is always observed.
centrifugal force was made up. it's still centripetal force.

Mad Caddie
11/15/04, 10:17 PM
I always thought it was constipational force??

venus/bacchus
11/15/04, 10:23 PM
centrifugal force was made up. it's still centripetal force.
Actually it's technically the opposite. The centripetal force keeps the rotating object in the circle, while the "centrifugal" keeps it from flying away. Centrifugal force in reality is just the tendency of an object to maintain its inertial frame of reference.

ohlookitspaul
11/15/04, 10:34 PM
Actually it's technically the opposite. The centripetal force keeps the rotating object in the circle, while the "centrifugal" keeps it from flying away. Centrifugal force in reality is just the tendency of an object to maintain its inertial frame of reference.
ok yeah, after consulting google and my old high school physics book (which i for some reason still own), you're right. this explains it well: http://www.newton.dep.anl.gov/askasci/phy00/phy00305.htm

brandnewtbs23
11/18/04, 04:18 PM
and you have to take into account santas magic

aolsux
11/18/04, 04:46 PM
and you have to take into account santas magic
he's like that

richter915
01/17/06, 08:16 PM
ah! I wanted to repost this sooner but couldn't find it. Enjoy children as science ruins your fun once again!

aminorthreat55
01/17/06, 08:29 PM
ah! I wanted to repost this sooner but couldn't find it. Enjoy children as science ruins your fun once again!
I loved this thread and love you for bumping it. And I'm drunk.

richter915
01/17/06, 08:29 PM
this thread reminds me of how amazing Tony and Alan were.

aminorthreat55
01/17/06, 08:30 PM
this thread reminds me of how amazing Tony and Alan were.
Alan now lives 15 minutes from me. I'm adamant that in the next month we will drink together.

richter915
01/17/06, 08:36 PM
Alan now lives 15 minutes from me. I'm adamant that in the next month we will drink together.
that would be amazing. make videos and YSI.

aminorthreat55
01/17/06, 08:37 PM
that would be amazing. make videos and YSI.
K.

aminorthreat55
01/17/06, 08:37 PM
K.
I'm also gonna try and get him to guest host my radio show that starts in 2 weeks.

osunfg
01/18/06, 06:13 AM
and you have to take into account santas magic
magic aka the 1985674 lines of coke he does before he says "THUMBS UP LETS DO THISSSS"

richter915
01/18/06, 11:05 AM
magic aka the 1985674 lines of coke he does before he says "THUMBS UP LETS DO THISSSS"
haha pretty much.