• Log InLog In
  • Register
Liquid`
Team Liquid Liquipedia
EDT 22:09
CEST 04:09
KST 11:09
  • 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
[ASL19] Finals Recap: Standing Tall9HomeStory Cup 27 - Info & Preview18Classic wins Code S Season 2 (2025)16Code S RO4 & Finals Preview: herO, Rogue, Classic, GuMiho0TL Team Map Contest #5: Presented by Monster Energy6
Community News
[BSL20] Non-Korean Championship 4x BSL + 4x China1Flash Announces Hiatus From ASL63Weekly Cups (June 23-29): Reynor in world title form?13FEL Cracov 2025 (July 27) - $8000 live event22Esports World Cup 2025 - Final Player Roster16
StarCraft 2
General
Program: SC2 / XSplit / OBS Scene Switcher The SCII GOAT: A statistical Evaluation Statistics for vetoed/disliked maps Weekly Cups (June 23-29): Reynor in world title form? PiG Sty Festival #5: Playoffs Preview + Groups Recap
Tourneys
RSL: Revival, a new crowdfunded tournament series FEL Cracov 2025 (July 27) - $8000 live event Sparkling Tuna Cup - Weekly Open Tournament WardiTV Mondays Korean Starcraft League Week 77
Strategy
How did i lose this ZvP, whats the proper response Simple Questions Simple Answers
Custom Maps
[UMS] Zillion Zerglings
External Content
Mutation # 481 Fear and Lava Mutation # 480 Moths to the Flame Mutation # 479 Worn Out Welcome Mutation # 478 Instant Karma
Brood War
General
Player “Jedi” cheat on CSL SC uni coach streams logging into betting site Flash Announces Hiatus From ASL BW General Discussion Practice Partners (Official)
Tourneys
[BSL20] Non-Korean Championship 4x BSL + 4x China CSL Xiamen International Invitational The Casual Games of the Week Thread [BSL20] Grand Finals - Sunday 20:00 CET
Strategy
Simple Questions, Simple Answers I am doing this better than progamers do.
Other Games
General Games
Path of Exile Stormgate/Frost Giant Megathread Nintendo Switch Thread What do you want from future RTS games? Beyond All Reason
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
Heroes of StarCraft mini-set
TL Mafia
TL Mafia Community Thread Vanilla Mini Mafia
Community
General
US Politics Mega-thread Russo-Ukrainian War Thread Summer Games Done Quick 2025! Trading/Investing Thread Things Aren’t Peaceful in Palestine
Fan Clubs
SKT1 Classic Fan Club! Maru Fan Club
Media & Entertainment
Anime Discussion Thread [Manga] One Piece [\m/] Heavy Metal Thread
Sports
Formula 1 Discussion 2024 - 2025 Football Thread NBA General Discussion TeamLiquid Health and Fitness Initiative For 2023 NHL Playoffs 2024
World Cup 2022
Tech Support
Computer Build, Upgrade & Buying Resource Thread
TL Community
Blogs
Culture Clash in Video Games…
TrAiDoS
from making sc maps to makin…
Husyelt
Blog #2
tankgirl
StarCraft improvement
iopq
Trip to the Zoo
micronesia
Customize Sidebar...

Website Feedback

Closed Threads



Active: 715 users

Thinking Physics Question 6

Blogs > micronesia
Post a Reply
1 2 Next All
micronesia
Profile Blog Joined July 2006
United States24668 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 States24668 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 States528 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 States9616 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 States24668 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 States24668 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
Next event in 8h 51m
[ Submit Event ]
Live Streams
Refresh
StarCraft 2
Nina 234
Livibee 187
RuFF_SC2 144
ProTech70
StarCraft: Brood War
Artosis 836
Noble 26
Icarus 6
LuMiX 4
Dota 2
monkeys_forever1018
Counter-Strike
tarik_tv7143
Fnx 1940
Stewie2K1109
Super Smash Bros
Mew2King89
Heroes of the Storm
Khaldor194
Other Games
summit1g10967
fl0m581
ViBE245
Maynarde176
Organizations
Other Games
gamesdonequick51819
BasetradeTV123
StarCraft 2
Blizzard YouTube
StarCraft: Brood War
BSLTrovo
sctven
[ Show 13 non-featured ]
StarCraft 2
• Berry_CruncH189
• davetesta41
• AfreecaTV YouTube
• intothetv
• Kozan
• IndyKCrew
• LaughNgamezSOOP
• Migwel
• sooper7s
StarCraft: Brood War
• Azhi_Dahaki1
• BSLYoutube
• STPLYoutube
• ZZZeroYoutube
Upcoming Events
Wardi Open
8h 51m
Replay Cast
21h 51m
Sparkling Tuna Cup
1d 7h
WardiTV European League
1d 13h
MaNa vs sebesdes
Mixu vs Fjant
ByuN vs HeRoMaRinE
ShoWTimE vs goblin
Gerald vs Babymarine
Krystianer vs YoungYakov
PiGosaur Monday
1d 21h
The PondCast
2 days
WardiTV European League
2 days
Jumy vs NightPhoenix
Percival vs Nicoract
ArT vs HiGhDrA
MaxPax vs Harstem
Scarlett vs Shameless
SKillous vs uThermal
uThermal 2v2 Circuit
2 days
Replay Cast
2 days
RSL Revival
3 days
ByuN vs SHIN
Clem vs Reynor
[ Show More ]
Replay Cast
3 days
RSL Revival
4 days
Classic vs Cure
FEL
4 days
RSL Revival
5 days
FEL
5 days
FEL
5 days
Sparkling Tuna Cup
6 days
RSL Revival
6 days
FEL
6 days
Liquipedia Results

Completed

BSL Season 20
HSC XXVII
Heroes 10 EU

Ongoing

JPL Season 2
Acropolis #3
KCM Race Survival 2025 Season 2
CSL 17: 2025 SUMMER
Copa Latinoamericana 4
Jiahua Invitational
Championship of Russia 2025
RSL Revival: Season 1
Murky Cup #2
BLAST.tv Austin Major 2025
ESL Impact League Season 7
IEM Dallas 2025
PGL Astana 2025
Asian Champions League '25
BLAST Rivals Spring 2025
MESA Nomadic Masters
CCT Season 2 Global Finals
IEM Melbourne 2025

Upcoming

2025 ACS Season 2: Qualifier
CSLPRO Last Chance 2025
CSL Xiamen Invitational
2025 ACS Season 2
CSLPRO Chat StarLAN 3
K-Championship
uThermal 2v2 Main Event
SEL Season 2 Championship
FEL Cracov 2025
Esports World Cup 2025
StarSeries Fall 2025
FISSURE Playground #2
BLAST Open Fall 2025
BLAST Open Fall Qual
Esports World Cup 2025
BLAST Bounty Fall 2025
BLAST Bounty Fall Qual
IEM Cologne 2025
FISSURE Playground #1
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.