On a day when the atmospheric pressure is P = 1 atm and the temperature is 22!C,
ID: 1979852 • Letter: O
Question
On a day when the atmospheric pressure isP = 1 atm and the temperature is 22!C, a
diving bell in the shape of a cylinder 4.9mtall,
closed at the upper end, is lowered into water
to aid in the construction of an underground
foundation for a bridge tower. The water
inside the diving bell rises to within 2.3 m of
the top, and the temperature drops to 7.8!C.
The acceleration of gravity is 9.8 m/s2 .
Find the air pressure inside the bell.
How far below the surface of the water is the
bell located? (In actual use, additional air is
pumped in, forcing the water out to provide
working space for the construction workers).
Explanation / Answer
solved a similar question already with different numbers.. i put the question and the answer.. hope it helps!! :) kindly rate a lifesaver :)
On a day when the atmospheric pressure is
P = 1 atm and the temperature is 26?C, a
diving bell in the shape of a cylinder 5.6mtall,
closed at the upper end, is lowered into water
to aid in the construction of an underground
foundation for a bridge tower. The water
inside the diving bell rises to within 1.6 m of
the top, and the temperature drops to 7.6?C.
The acceleration of gravity is 9.8 m/s2 .
Find the air pressure inside the bell.
Answer in units of atm.
How far below the surface of the water is the
bell located? (In actual use, additional air is
pumped in, forcing the water out to provide
working space for the construction workers).
Answer in units of m.
ANSWER:
assuming the amount of air inside the bell isconstant during it is loweredinto water.
roughly, we can use the equation as ideal gas:
P.V/T=const
P: pressure of air inside the bell
V: volume of the air
T: (kelvin) temperature of the air
the area of cylinder is also constant, so we have: P.h/T=const
P1.h1/T1=P2.h2/T2 (*)
P1=atmospheric pressure =P=1atm ;
h1=5.6 m ; h2=1.6 m
T1=26+273=299 K ; T2=7.6 +273=280.6 K
from (*) we get: P2= 3.28 atm
dark area is air inside the bell, red line is the surface betweenwater and air inside the bell.
So the pressure of air inside the bell
P2=.g.(h+1.6) + P => h=21.6 (m) (h is thedistance need to be calculated.)
( to solve it, P2 need to be changed to Pa) =1000(kg.m-3)
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