This preview shows page 1. Sign up to view the full content.
30. (a) The pressure (including the contribution from the atmosphere) at a depth of
h
top
=
L
/2 (corresponding to the top of the block) is
53
2
5
top
atm
top
1.01 10 Pa
(1030 kg/m )(9.8 m/s )(0.300 m)
1.04
10 Pa
pp
g
h
ρ
=+
=×
+
=
×
where the unit Pa (Pascal) is equivalent to N/m
2
. The force on the top surface (of area
A
= L
2
= 0.36 m
2
) is
F
top
=
p
top
A
= 3.75
×
10
4
N.
(b) The pressure at a depth of
h
bot
= 3
L
/2 (that of the bottom of the block) is
2
5
bot
atm
bot
(1030 kg/m )(9.8 m/s )(0.900 m) 1.10
10 Pa
g
h
=
×
+
=
×
where we recall that the unit Pa (Pascal) is equivalent to N/m
2
. The force on the bottom
surface is
F
bot
=
p
bot
A
= 3.96
×
10
4
N.
(c) Taking the difference
F
bot
–
F
top
cancels the contribution from the atmosphere
This is the end of the preview. Sign up
to
access the rest of the document.
 Spring '08
 Any
 Physics

Click to edit the document details