 |
|
|
|
|
|
|
|
|
 |
|
|||||||
 |
 |
 |
 |
 |
 |
 |
|
|
 |
|
|||||||
 |
|
|||||||
 |
 |
|
||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
 |
|
|||||||
PRINCIPAL AXES EXAMPLES
EXAMPLE I
State the principal axes for the two-dimensional body shown in Figure 1↓.
ANSWER: Because of the symmetry through the point C, the products of inertia vanish for any line that goes through C. Therefore, any line drawn through C will be a principal axis.
EXAMPLE II
State the principal axes for a sphere.
ANSWER: Again, because of symmetry, a sphere will have all 3 axes drawn in any direction through C as a principal axis.