90_Problem CHAPTER 9

90_Problem CHAPTER 9 - PROBLEM 9.79 Determine for the...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
PROBLEM 9.79 Determine for the quarter ellipse of Problem 9.67 the moments of inertia and the product of inertia with respect to new axes obtained by rotating the x and y axes about O ( a ) through o 45 counterclockwise, ( b ) through o 30 clockwise. SOLUTION From Figure 9.12: () ( ) 3 2 16 x I aa π = 4 8 a = ( ) 3 2 16 y I = 4 2 a = From Problem 9.67: 4 1 2 xy I a = First note 44 4 11 5 22 8 2 1 6 xy I Ia a a ππ  += + =   4 3 8 2 1 6 I a a −= = Now use Equations (9.18), (9.19), and (9.20). Equation (9.18): cos2 sin 2 xx yx y x y II I I θ
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.
Ask a homework question - tutors are online