27. (a) We use the expression for the variation of pressure with height in an
incompressible fluid:
p
2
=
p
1
–
ρ
g
(
y
2
–
y
1
). We take
y
1
to be at the surface of Earth, where
the pressure is
p
1
= 1.01
×
10
5
Pa, and
y
2
to be at the top of the atmosphere, where the
pressure is
p
2
= 0. For this calculation, we take the density to be uniformly 1.3 kg/m
3
.
Then,
5
3
1
21
32
1.01
10 Pa
7.9
10 m = 7.9 km.
(1.3 kg/m )(9.8m/s )
p
yy
g
×
−=
=
=×
(b) Let
h
be the height of the atmosphere. Now, since the density varies with altitude, we
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 06/03/2011 for the course PHY 2049 taught by Professor Any during the Spring '08 term at University of Florida.
 Spring '08
 Any
 Physics

Click to edit the document details