COSMOS: Complete Online Solutions Manual Organization System
Chapter 9, Solution 13.
At
x = 2a, y = b : 2a = kb3
2a 3
y
b3
Then
x=
or
y =
Now
I y = ∫ x 2dA
Then
I y = ∫ a x2
b
( 2a )
=
=
=
1
b
( 2a )
1
3
x 3 dx
7
b
( 2a )
x3
dA = ydx
2a
=
1
1
3
1
3
b
1
( 2a ) 3
2a
∫ a x 3 dx
3 103
x
10
3b
10 ( 2a )
1
3
2a
a
2a 103 − a 103
( )
10
3ba3 103
2 − 1 3
1
10 ( 2 ) 3
= 2.1619a3b
or I y = 2.16a3b