This discussion is closed.
nikk
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#21
Report 18 years ago
#21
(Original post by NikNak)
I know but if you can have two pockets of air that are the different densities but are the same pressure (obviously the volumes would be different).
if the air in the ballon is a higher temperature then the volume of the air MUST decrease in volume for the pressure to remain the same of the outside of the ballon. This means the air inside the ballon would be less dense and so it rises?
0
elpaw
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#22
Report 18 years ago
#22
(Original post by NikNak)
I know but if you can have two pockets of air that are the different densities but are the same pressure (obviously the volumes would be different).
yes, one's molecules would be moving faster than the other's
0
Unregistered
Badges:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#23
Report 18 years ago
#23
Heres the actual Q Ive got

WHATEVER THE TEMPERATURE OF THE AIR IN THE BALLOON, ITS PRESSURE WILL BE THE SAME AS THE SURROUNDING AIR.
EXPLAIN WHY.

Thanks everyone, im really grateful

Lol, cud someone summarise an answer for me please!!!
0
elpaw
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#24
Report 18 years ago
#24
(Original post by NikNak)
if the air in the ballon is a higher temperature then the volume of the air MUST decrease in volume for the pressure to remain the same of the outside of the ballon. This means the air inside the ballon would be less dense and so it rises?
yes
0
nikk
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#25
Report 18 years ago
#25
(Original post by elpaw)
yes
so thats the answer for the unreg dude?
0
Unregistered
Badges:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#26
Report 18 years ago
#26
NOOOOOOOOOO!! Im not that Unreg.maskall person, urgh

Im just a confused physics student!!! So cud erm, someone summarise an answer for me then!! PLEASE!!!
0
elpaw
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#27
Report 18 years ago
#27
(Original post by NikNak)
so thats the answer for the unreg dude?
probably
0
elpaw
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#28
Report 18 years ago
#28
(Original post by Unregistered)
NOOOOOOOOOO!! Im not that Unreg.maskall person, urgh

Im just a confused physics student!!! So cud erm, someone summarise an answer for me then!! PLEASE!!!
who mentioned maskall? :suspicious eye:
0
Vienna
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#29
Report 18 years ago
#29
(Original post by Unregistered)
NOOOOOOOOOO!! Im not that Unreg.maskall person, urgh

Im just a confused physics student!!! So cud erm, someone summarise an answer for me then!! PLEASE!!!
have the decency to do it yourself seeing as theyve given you the answer.
0
Unregistered
Badges:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#30
Report 18 years ago
#30
please, i promise u. Im not that annying kid who gives abuse
0
nikk
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#31
Report 18 years ago
#31
(Original post by Unregistered)
NOOOOOOOOOO!! Im not that Unreg.maskall person, urgh

Im just a confused physics student!!! So cud erm, someone summarise an answer for me then!! PLEASE!!!
K, so the air in the ballon increases in temp, and expands. The pressure remains the same inside and out because the volume of air inside the ballon decreases. So although the pressure is the same, the volume of air inside the ballon is lower.
0
elpaw
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#32
Report 18 years ago
#32
(Original post by NikNak)
K, so the air in the ballon increases in temp, and expands. The pressure remains the same inside and out because the volume of air inside the ballon decreases. So although the pressure is the same, the volume of air inside the ballon is lower.
no, the volume increases.
0
Unregistered
Badges:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#33
Report 18 years ago
#33
Hmm, ok.
so how comes the volume of air decreases. How does this happen?
Thanks for replying by the way.
0
nikk
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#34
Report 18 years ago
#34
(Original post by elpaw)
no, the volume increases.
oh yeah sorry....
0
cimmie
Badges: 0
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#35
Report 18 years ago
#35
(p*V)/T = const.
0
Michael Beaver
Badges: 0
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#36
Report 18 years ago
#36
Hot air balloons thrust can be found using Archimedes' principle.

The air is heated so it is less dense we are agreed. Its pressure is the same at the hole in the bottom agreed.

^ - z direction

dp/dz = (rho) x g - outside (inside is more complicated)

obviously the pressure gradient would be different if the balloon was solid but the balloon is pressurised by the air outside because the the baloon cannot support a stress. So is the same. Agreed???

The balloon floats because the density of the air inside is lower than outside so the balloon weighs less than the air around it:

F = (rho) x volume - weight

where the volume and weight refers to the balloon and basket and the air in the balloon.

I dont like what I have written I need to think about this.
0
X
new posts
Back
to top
Latest
My Feed

See more of what you like on
The Student Room

You can personalise what you see on TSR. Tell us a little about yourself to get started.

Personalise

How would you describe the quality of the digital skills you're taught at school?

Excellent (37)
9.51%
Okay (113)
29.05%
A bit lacking (147)
37.79%
Not good at all (92)
23.65%

Watched Threads

View All