• Log InLog In
  • Register
Liquid`
Team Liquid Liquipedia
EST 08:59
CET 14:59
KST 22:59
  • Home
  • Forum
  • Calendar
  • Streams
  • Liquipedia
  • Features
  • Store
  • EPT
  • TL+
  • StarCraft 2
  • Brood War
  • Smash
  • Heroes
  • Counter-Strike
  • Overwatch
  • Liquibet
  • Fantasy StarCraft
  • TLPD
  • StarCraft 2
  • Brood War
  • Blogs
Forum Sidebar
Events/Features
News
Featured News
RSL Season 3 - Playoffs Preview0RSL Season 3 - RO16 Groups C & D Preview0RSL Season 3 - RO16 Groups A & B Preview2TL.net Map Contest #21: Winners12Intel X Team Liquid Seoul event: Showmatches and Meet the Pros10
Community News
Weekly Cups (Nov 24-30): MaxPax, Clem, herO win1BGE Stara Zagora 2026 announced14[BSL21] Ro.16 Group Stage (C->B->A->D)4Weekly Cups (Nov 17-23): Solar, MaxPax, Clem win3RSL Season 3: RO16 results & RO8 bracket13
StarCraft 2
General
SC2 Proleague Discontinued; SKT, KT, SGK, CJ disband Weekly Cups (Nov 24-30): MaxPax, Clem, herO win BGE Stara Zagora 2026 announced Information Request Regarding Chinese Ladder SC: Evo Complete - Ranked Ladder OPEN ALPHA
Tourneys
$5,000+ WardiTV 2025 Championship Constellation Cup - Main Event - Stellar Fest RSL Revival: Season 3 Tenacious Turtle Tussle [Alpha Pro Series] Nice vs Cure
Strategy
Custom Maps
Map Editor closed ?
External Content
Mutation # 502 Negative Reinforcement Mutation # 501 Price of Progress Mutation # 500 Fright night Mutation # 499 Chilling Adaptation
Brood War
General
Which season is the best in ASL? BGH Auto Balance -> http://bghmmr.eu/ FlaSh's Valkyrie Copium BW General Discussion A cwal.gg Extension - Easily keep track of anyone
Tourneys
[Megathread] Daily Proleagues [BSL21] RO16 Group B - Sunday 21:00 CET [BSL21] RO16 Group C - Saturday 21:00 CET Small VOD Thread 2.0
Strategy
Game Theory for Starcraft How to stay on top of macro? Current Meta PvZ map balance
Other Games
General Games
Should offensive tower rushing be viable in RTS games? The Perfect Game Path of Exile Nintendo Switch Thread Stormgate/Frost Giant Megathread
Dota 2
Official 'what is Dota anymore' discussion
League of Legends
Heroes of the Storm
Simple Questions, Simple Answers Heroes of the Storm 2.0
Hearthstone
Deck construction bug Heroes of StarCraft mini-set
TL Mafia
Mafia Game Mode Feedback/Ideas TL Mafia Community Thread
Community
General
US Politics Mega-thread Russo-Ukrainian War Thread Things Aren’t Peaceful in Palestine The Big Programming Thread Artificial Intelligence Thread
Fan Clubs
White-Ra Fan Club
Media & Entertainment
[Manga] One Piece Movie Discussion! Anime Discussion Thread
Sports
Formula 1 Discussion 2024 - 2026 Football Thread NBA General Discussion MLB/Baseball 2023
World Cup 2022
Tech Support
Computer Build, Upgrade & Buying Resource Thread
TL Community
Where to ask questions and add stream? The Automated Ban List
Blogs
Esports Earnings: Bigger Pri…
TrAiDoS
Thanks for the RSL
Hildegard
Saturation point
Uldridge
DnB/metal remix FFO Mick Go…
ImbaTosS
Customize Sidebar...

Website Feedback

Closed Threads



Active: 1600 users

Thinking Physics Question 6

Blogs > micronesia
Post a Reply
1 2 Next All
micronesia
Profile Blog Joined July 2006
United States24744 Posts
October 19 2008 16:56 GMT
#1
For those who didn't read the introductory entry, head over to http://www.teamliquid.net/blogs/viewblog.php?topic_id=79275

Last time the question of the week was:

Question 5
Gravity
Imagine two small droplets of water floating in empty space. Our conventional theory of gravity says that they will attract and accelerate towards each other. But what if instead you had water everywhere except for two small bubbles (empty spaces) nearby in the large mass of water?

The bubbles would:

a) Move Apart
b) Not Move At All
c) Move towards each other (attract)


The answer is c. You can think about the net gravity at a point due to the contributions from specific regions of water. Imagine point p equidistant from region R and region Q, both filled with water. The gravitational field from each region cancels, and results in 0 gravitational field at p.

Now imagine that region R is an air bubble, and region Q is still water. The gravity field at p is now towards Q because R does not provide any field. A rock floating at p would get pulled towards Q. But what about an air bubble originally at P? Bubbles tend to go the opposite direction that a rock would! I would rate this 3/5 difficulty because it takes a simple situation and complicates it.

Luddite provided an interesting explanation:
We can just think of the bubbles as particles of negative mass (holes, basically). However, since gravity goes as the SQUARE of the mass, the negative sign cancels out, so they still attract.


doghunter was the first user to get the question right, but I honestly don't know if his explanation works or not. Same with renezerg. MasterofChaos I don't think I understand your answer, however, I don't believe the bubbles need to be shielded necessarily.

Question 6
Fluids
Three icebergs float in bathtubs brim full with ice-cold water. Iceberg A has a big air bubble in it. Iceberg W has some unfrozen water in it. Iceberg S has a railroad spike frozen in it. When they melt, what will happen?

a) Only the water in S will spill over
b) The water in S will get lower and the water in A and W will stay exactly brim full
c) The water in A will stay brim full, the water in W will spill over, and the water in S will spill over
d) All will spill over
e) All stay exactly brim full

As always, post your answers in spoilers and provide explanations.

*****
ModeratorThere are animal crackers for people and there are people crackers for animals.
kramus
Profile Blog Joined November 2007
United States1259 Posts
October 19 2008 17:03 GMT
#2
+ Show Spoiler +
i'm guessing e, since the level of the water (brim full) already takes into account the "objects" in the icebergs
SCC-Faust
Profile Blog Joined November 2007
United States3736 Posts
October 19 2008 17:15 GMT
#3
+ Show Spoiler +
B
I want to fuck Soulkey with a Zelderan.
micronesia
Profile Blog Joined July 2006
United States24744 Posts
Last Edited: 2008-10-19 17:18:22
October 19 2008 17:18 GMT
#4
SCC-Faust provide an explanation you emo-blogging self-deprecating son of a broodling.
ModeratorThere are animal crackers for people and there are people crackers for animals.
kramus
Profile Blog Joined November 2007
United States1259 Posts
Last Edited: 2008-10-19 17:36:25
October 19 2008 17:25 GMT
#5
On October 20 2008 02:03 kramus wrote:
+ Show Spoiler +
i'm guessing e, since the level of the water (brim full) already takes into account the "objects" in the icebergs

+ Show Spoiler +
actually if something more dense than ice (or water?) were in the ice then it seems like the water level should decrease after the ice melts, because it would have been displacing more water than it "should have" since it had more mass in the same volume

edit: meant to change to B
HypnoticPoo
Profile Blog Joined March 2008
Singapore291 Posts
Last Edited: 2008-10-19 17:26:41
October 19 2008 17:26 GMT
#6
Doing this for a friend:
+ Show Spoiler +
ANS: C
explanation: the empty space in in ice A will compensate volume, for ice B, when water is frozen, vol drops unusually, assuming baths are full, the internal water will overcompensate..therefore it will spill..i dont know/never bloody see an railroad spike before..and A and B agrees with answer C.
MEOW.
MasterOfChaos
Profile Blog Joined April 2007
Germany2896 Posts
October 19 2008 17:34 GMT
#7
+ Show Spoiler +
b)
For floating objects only the total mass of it determines the amount of water in moves aside.
So the phase transition of A and W doesn't make a difference. S is different, because before it melts the amount of water moved aside is proportional to the total mass. Afterwards the spike sinks to the ground where it will move only the volume of the spike itself aside which is less than the equivalent of the mass of the floating so the water sinks.
LiquipediaOne eye to kill. Two eyes to live.
LaLuSh
Profile Blog Joined April 2003
Sweden2358 Posts
October 19 2008 17:47 GMT
#8
+ Show Spoiler +
e) The mass won't change in any of the tubs.

I just read masterofchaos' spoiler though and it seems pretty reasonable, don't have any knowledge of those kind of mechanics though, my instinctive answer would've been e).
raiame
Profile Joined December 2007
United States421 Posts
October 19 2008 17:56 GMT
#9
+ Show Spoiler +
D. Ice is less dense than water. In the first two cases, the ice can displace no more than a volume of water equal to its weight, and when it melts, it expands to a volume that was larger than the initial volume of water displaced. In the third case, even if it were to be completely submerged in the water, the volume of the water after melting would exceed the volume of the ice before melting.
datscilly
Profile Blog Joined November 2007
United States529 Posts
October 19 2008 18:10 GMT
#10
+ Show Spoiler +
My answer is b) The water in S will get lower and the water in A and W will stay exactly brim full

A floating object displaces its weight in water. Any part of the iceberg which was ice turns into water when it melts, displacing the same volume before and after. So we can disregard the ice part of the icebergs.
The floating railroad spike displaces a volume of water equal to its weight, that is, a volume greater than the sinking railroad spike. The water in S will get lower as a result. Air displaces a little bit of water before, and none after, so the water in A will lower a little bit. For the third case, unfrozen water displaces the same amount of water before and afterwards.


eborp
Profile Blog Joined January 2008
United States266 Posts
Last Edited: 2008-10-19 19:24:50
October 19 2008 19:17 GMT
#11
+ Show Spoiler +

D
In order for the ice to melt the temperature around the ice-cold water needs to increase. When the temperature of water increases the volume taken by the water increases, so if each one of the tubs is full to begin with, then melting the ice will overflow the tub.

I think my answer is more chemistry than physics >.>
UMCP CSL NEEDS YOU!
brian
Profile Blog Joined August 2004
United States9633 Posts
Last Edited: 2008-10-19 20:12:27
October 19 2008 19:38 GMT
#12
SerpentFlame
Profile Blog Joined July 2008
415 Posts
Last Edited: 2008-10-19 19:45:08
October 19 2008 19:43 GMT
#13
+ Show Spoiler +

B
According to Archimede's principle, the weight of the water displaced = however much your object weighs. This means with just ice, the water level will not change since weight of ice = weight of water from iceberg melting. Since air weight is practically negligible, this will mean that iceberg A's water level will not move. The same explanation holds for iceberg W, because the water inside the iceberg can be treated separately from the iceberg via archimede's principle. However, when we look at iceberg S, the water displaced is far more than it was in either situation A or B. However, there is the same amount of ice. The same amount of ice is going to create the exact same amount of water, and because the spike doesn't change, more water is displaced by iceberg S than the amount of water that iceberg S will generate when melted. Thus tub S will grow lower in its water level
I Wannabe[WHITE], the very BeSt[HyO], like Yo Hwan EVER Oz.......
Slayer91
Profile Joined February 2006
Ireland23335 Posts
October 19 2008 20:10 GMT
#14
+ Show Spoiler +

I will assume the volume of ice is negligible
Iceberg A will release air which will go into the atmosphere and therefore not increase the volume
=> Brim full
Iceberg W has water in it however the weight of it is equal to the volume it displaces and since water has a relative density of 1
=> Brim full
Iceberg S has something heavier than water so it should displace more water than it would if it was released.
=> Water level lowers
Not sure if I remember the buoyancy (sp?) law correctly butok
That makes my answer:
=> (b)

micronesia
Profile Blog Joined July 2006
United States24744 Posts
October 19 2008 20:57 GMT
#15
On October 20 2008 04:38 Gene wrote:

Perfect. Gene wins let's move on.
ModeratorThere are animal crackers for people and there are people crackers for animals.
Too_MuchZerg
Profile Blog Joined February 2008
Finland2818 Posts
October 19 2008 21:09 GMT
#16
On October 20 2008 05:10 Slayer91 wrote:
+ Show Spoiler +

I will assume the volume of ice is negligible
Iceberg A will release air which will go into the atmosphere and therefore not increase the volume
=> Brim full
Iceberg W has water in it however the weight of it is equal to the volume it displaces and since water has a relative density of 1
=> Brim full
Iceberg S has something heavier than water so it should displace more water than it would if it was released.
=> Water level lowers
Not sure if I remember the buoyancy (sp?) law correctly butok
That makes my answer:
=> (b)



+ Show Spoiler +
get glass almost full of water and drop let say 10 coins and see what happens to water level
Insane Lane
Profile Blog Joined August 2008
United States397 Posts
October 19 2008 23:37 GMT
#17
What physics level/grade do you teach micronesia? If you do teach physics. I'm just curious... and do you like give these problems to your students as extra credit? lol
Grobyc
Profile Blog Joined June 2008
Canada18410 Posts
October 20 2008 00:44 GMT
#18
On October 20 2008 05:57 micronesia wrote:
Show nested quote +
On October 20 2008 04:38 Gene wrote:

Perfect. Gene wins let's move on.

Dammit he beat me to it..
If you watch Godzilla backwards it's about a benevolent lizard who helps rebuild a city and then moonwalks into the ocean.
micronesia
Profile Blog Joined July 2006
United States24744 Posts
October 20 2008 01:15 GMT
#19
On October 20 2008 08:37 Insane Lane wrote:
What physics level/grade do you teach micronesia? If you do teach physics. I'm just curious... and do you like give these problems to your students as extra credit? lol

I teach high school physics (gr 11-12). I do not give these as extra credit.
ModeratorThere are animal crackers for people and there are people crackers for animals.
TimeShifter
Profile Joined October 2008
Singapore235 Posts
October 20 2008 03:01 GMT
#20
+ Show Spoiler +
ANS: C
explanation: the empty space in in ice A will compensate volume, for ice B, when water is frozen, vol drops unusually, assuming baths are full, the internal water will overcompensate..therefore it will spill..i dont know/never seen a railroad spike before..and A and B agrees with answer C.


hi i am a high school student, its my first time on tl..i am doing Quantum Mechanics..is there a forum somewhere here?

i really am not very sure of the answer..i din't do fluids in school +.+
strawberries~
1 2 Next All
Please log in or register to reply.
Live Events Refresh
Wardi Open
12:00
#63
WardiTV891
TKL 288
Harstem274
Rex67
IntoTheiNu 1
Liquipedia
[ Submit Event ]
Live Streams
Refresh
StarCraft 2
Reynor 394
Lowko296
TKL 288
Harstem 274
Fuzer 211
Rex 67
StarCraft: Brood War
Britney 47062
Jaedong 1122
Soma 898
Mini 822
firebathero 784
actioN 718
Stork 557
BeSt 513
EffOrt 459
Light 440
[ Show more ]
Killer 258
hero 250
Zeus 173
PianO 171
sorry 89
Barracks 76
Pusan 76
Aegong 72
Hyun 68
Sharp 57
Snow 51
Shine 50
ggaemo 45
Mong 37
JYJ26
JulyZerg 24
Sacsri 21
zelot 21
soO 20
Bale 18
scan(afreeca) 17
Shinee 16
Noble 15
Terrorterran 14
ajuk12(nOOB) 13
SilentControl 9
Dota 2
singsing2833
Dendi744
XcaliburYe201
Gorgc115
boxi9814
Counter-Strike
olofmeister2814
zeus461
Heroes of the Storm
Khaldor1
Other Games
hiko522
crisheroes359
Mew2King121
Hui .115
QueenE41
Organizations
Other Games
gamesdonequick792
StarCraft 2
Blizzard YouTube
StarCraft: Brood War
BSLTrovo
sctven
[ Show 14 non-featured ]
StarCraft 2
• StrangeGG 69
• Light_VIP 23
• AfreecaTV YouTube
• intothetv
• Kozan
• IndyKCrew
• LaughNgamezSOOP
• Migwel
• sooper7s
StarCraft: Brood War
• BSLYoutube
• STPLYoutube
• ZZZeroYoutube
Dota 2
• C_a_k_e 993
• WagamamaTV291
Upcoming Events
Monday Night Weeklies
3h 1m
StarCraft2.fi
3h 1m
Replay Cast
10h 1m
Wardi Open
22h 1m
StarCraft2.fi
1d 3h
PiGosaur Monday
1d 11h
Wardi Open
1d 22h
StarCraft2.fi
2 days
Replay Cast
2 days
The PondCast
2 days
[ Show More ]
Replay Cast
3 days
Korean StarCraft League
4 days
CranKy Ducklings
4 days
SC Evo League
4 days
BSL 21
5 days
Sziky vs OyAji
Gypsy vs eOnzErG
Sparkling Tuna Cup
5 days
BSL 21
6 days
Bonyth vs StRyKeR
Tarson vs Dandy
Replay Cast
6 days
Wardi Open
6 days
Liquipedia Results

Completed

Proleague 2025-11-28
RSL Revival: Season 3
Eternal Conflict S1

Ongoing

C-Race Season 1
IPSL Winter 2025-26
KCM Race Survival 2025 Season 4
YSL S2
BSL Season 21
CSCL: Masked Kings S3
Slon Tour Season 2
Acropolis #4 - TS3
META Madness #9
Light HT
SL Budapest Major 2025
ESL Impact League Season 8
BLAST Rivals Fall 2025
IEM Chengdu 2025
PGL Masters Bucharest 2025
Thunderpick World Champ.
CS Asia Championships 2025
ESL Pro League S22
StarSeries Fall 2025
FISSURE Playground #2

Upcoming

BSL 21 Non-Korean Championship
Acropolis #4
IPSL Spring 2026
Bellum Gens Elite Stara Zagora 2026
HSC XXVIII
RSL Offline Finals
WardiTV 2025
Kuram Kup
PGL Cluj-Napoca 2026
IEM Kraków 2026
BLAST Bounty Winter 2026
BLAST Bounty Winter 2026: Closed Qualifier
eXTREMESLAND 2025
TLPD

1. ByuN
2. TY
3. Dark
4. Solar
5. Stats
6. Nerchio
7. sOs
8. soO
9. INnoVation
10. Elazer
1. Rain
2. Flash
3. EffOrt
4. Last
5. Bisu
6. Soulkey
7. Mini
8. Sharp
Sidebar Settings...

Advertising | Privacy Policy | Terms Of Use | Contact Us

Original banner artwork: Jim Warren
The contents of this webpage are copyright © 2025 TLnet. All Rights Reserved.