• Log InLog In
  • Register
Liquid`
Team Liquid Liquipedia
EST 06:32
CET 12:32
KST 20:32
  • 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
Behind the Blue - Team Liquid History Book15Clem wins HomeStory Cup 289HomeStory Cup 28 - Info & Preview13Rongyi Cup S3 - Preview & Info8herO wins SC2 All-Star Invitational14
Community News
ACS replaced by "ASL Season Open" - Starts 21/0221LiuLi Cup: 2025 Grand Finals (Feb 10-16)26Weekly Cups (Feb 2-8): Classic, Solar, MaxPax win2Nexon's StarCraft game could be FPS, led by UMS maker10PIG STY FESTIVAL 7.0! (19 Feb - 1 Mar)14
StarCraft 2
General
How do you think the 5.0.15 balance patch (Oct 2025) for StarCraft II has affected the game? Nexon's StarCraft game could be FPS, led by UMS maker Terran Scanner Sweep Behind the Blue - Team Liquid History Book Weekly Cups (Jan 12-18): herO, MaxPax, Solar win
Tourneys
Sparkling Tuna Cup - Weekly Open Tournament RSL Season 4 announced for March-April PIG STY FESTIVAL 7.0! (19 Feb - 1 Mar) LiuLi Cup: 2025 Grand Finals (Feb 10-16) RSL Revival: Season 4 Korea Qualifier (Feb 14)
Strategy
Custom Maps
Map Editor closed ? [A] Starcraft Sound Mod
External Content
The PondCast: SC2 News & Results Mutation # 512 Overclocked Mutation # 511 Temple of Rebirth Mutation # 510 Safety Violation
Brood War
General
ACS replaced by "ASL Season Open" - Starts 21/02 Which units you wish saw more use in the game? StarCraft player reflex TE scores [ASL21] Potential Map Candidates Gypsy to Korea
Tourneys
Escore Tournament StarCraft Season 1 [Megathread] Daily Proleagues Small VOD Thread 2.0 KCM Race Survival 2026 Season 1
Strategy
Fighting Spirit mining rates Zealot bombing is no longer popular? Simple Questions, Simple Answers Current Meta
Other Games
General Games
Path of Exile Nintendo Switch Thread Diablo 2 thread Battle Aces/David Kim RTS Megathread ZeroSpace 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
TL Mafia Community Thread Mafia Game Mode Feedback/Ideas Vanilla Mini Mafia
Community
General
US Politics Mega-thread Ask and answer stupid questions here! Things Aren’t Peaceful in Palestine European Politico-economics QA Mega-thread The Games Industry And ATVI
Fan Clubs
The IdrA Fan Club The herO Fan Club!
Media & Entertainment
[Req][Books] Good Fantasy/SciFi books [Manga] One Piece Anime Discussion Thread
Sports
2024 - 2026 Football Thread
World Cup 2022
Tech Support
TL Community
The Automated Ban List
Blogs
ADHD And Gaming Addiction…
TrAiDoS
My 2025 Magic: The Gathering…
DARKING
Life Update and thoughts.
FuDDx
How do archons sleep?
8882
StarCraft improvement
iopq
Customize Sidebar...

Website Feedback

Closed Threads



Active: 1981 users

Thinking Physics Question 6

Blogs > micronesia
Post a Reply
1 2 Next All
micronesia
Profile Blog Joined July 2006
United States24753 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 States24753 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 States9636 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 States24753 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 States24753 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
LiuLi Cup
11:00
2025 Grand Finals Playoffs
Maru vs ReynorLIVE!
Serral vs Rogue
RotterdaM1437
ComeBackTV 819
PiGStarcraft446
IndyStarCraft 272
BRAT_OK 174
Rex134
3DClanTV 64
IntoTheiNu 18
Liquipedia
Sparkling Tuna Cup
10:00
Weekly #119
Krystianer vs YoungYakovLIVE!
ByuN vs TBD
CranKy Ducklings93
LiquipediaDiscussion
[ Submit Event ]
Live Streams
Refresh
StarCraft 2
RotterdaM 1437
PiGStarcraft446
IndyStarCraft 272
BRAT_OK 174
Rex 134
EmSc Tv 10
StarCraft: Brood War
Britney 20771
Rain 2934
Sea 2039
actioN 1268
Flash 1223
firebathero 1075
Stork 336
Soulkey 316
Hyun 254
Mini 186
[ Show more ]
Rush 166
Last 153
EffOrt 135
Sharp 65
Leta 57
ToSsGirL 44
ggaemo 43
Sea.KH 36
sorry 34
Shine 23
sSak 22
Backho 21
JYJ 20
GoRush 19
soO 16
Movie 14
zelot 10
IntoTheRainbow 10
Sacsri 9
JulyZerg 8
Calm 0
Dota 2
XaKoH 923
XcaliburYe250
Fuzer 222
NeuroSwarm131
Counter-Strike
olofmeister3842
x6flipin259
Super Smash Bros
Mew2King122
Heroes of the Storm
Khaldor125
Other Games
gofns13976
crisheroes238
MindelVK11
Organizations
Counter-Strike
PGL39497
StarCraft: Brood War
lovetv 16
StarCraft 2
EmSc Tv 10
EmSc2Tv 10
Blizzard YouTube
StarCraft: Brood War
BSLTrovo
sctven
[ Show 13 non-featured ]
StarCraft 2
• AfreecaTV YouTube
• intothetv
• Kozan
• IndyKCrew
• LaughNgamezSOOP
• Migwel
• sooper7s
StarCraft: Brood War
• BSLYoutube
• STPLYoutube
• ZZZeroYoutube
Dota 2
• lizZardDota295
League of Legends
• Jankos1886
• Stunt510
Upcoming Events
Ladder Legends
6h 28m
Replay Cast
12h 28m
Replay Cast
21h 28m
Wardi Open
1d
Monday Night Weeklies
1d 5h
OSC
1d 12h
WardiTV Winter Champion…
2 days
Replay Cast
2 days
WardiTV Winter Champion…
3 days
Replay Cast
3 days
[ Show More ]
PiG Sty Festival
3 days
The PondCast
3 days
KCM Race Survival
3 days
WardiTV Winter Champion…
4 days
Replay Cast
4 days
PiG Sty Festival
4 days
Epic.LAN
5 days
Replay Cast
5 days
PiG Sty Festival
5 days
CranKy Ducklings
5 days
Epic.LAN
6 days
Replay Cast
6 days
PiG Sty Festival
6 days
Sparkling Tuna Cup
6 days
Liquipedia Results

Completed

Proleague 2026-02-14
Rongyi Cup S3
Underdog Cup #3

Ongoing

KCM Race Survival 2026 Season 1
LiuLi Cup: 2025 Grand Finals
Nations Cup 2026
PGL Cluj-Napoca 2026
IEM Kraków 2026
BLAST Bounty Winter 2026
BLAST Bounty Winter Qual
eXTREMESLAND 2025
SL Budapest Major 2025

Upcoming

Escore Tournament S1: King of Kings
[S:21] ASL SEASON OPEN 1st Round
[S:21] ASL SEASON OPEN 1st Round Qualifier
[S:21] ASL SEASON OPEN 2nd Round
[S:21] ASL SEASON OPEN 2nd Round Qualifier
Acropolis #4
IPSL Spring 2026
HSC XXIX
uThermal 2v2 2026 Main Event
Bellum Gens Elite Stara Zagora 2026
RSL Revival: Season 4
WardiTV Winter 2026
BLAST Rivals Spring 2026
CCT Season 3 Global Finals
FISSURE Playground #3
IEM Rio 2026
PGL Bucharest 2026
Stake Ranked Episode 1
BLAST Open Spring 2026
ESL Pro League Season 23
ESL Pro League Season 23
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 © 2026 TLnet. All Rights Reserved.