- #1
vetgirl1990
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Homework Statement
A helium balloon of mass 0.2kg and volume 1m3 is attached to a long thin rope of mass density 1g/m. The coils of rope lay flat on the ground, so that as the balloon moves up the rope unwinds without resistance. How high will the balloon rise?
Air density = 1.204kg/m3
a) 1204m
b) 1004m
c) 602m
d) 502m
e) none of the above
Homework Equations
P = pgh
The Attempt at a Solution
I think the balloon will stop rising when the pressure inside the balloon equals the pressure of the air on the outside.
Pressure of balloon:
P(balloon) = F/A
V = 4/3πr3 --> r = 0.6204m
SA = 4πr2 --> A = 4.835m2
P(balloon) = F/A = 0.4053N/m2
P(balloon)=P(air)
P(balloon)=ρairgh
0.4053 = (1204)(9.8)h
h=0.0000343m
This answer is clearly wrong... Not sure where I'm going wrong.