## 5 thoughts on “3.54”

1. Chad Carlson says:

When I compute the [A]^T*[M]*[A] my bottom right element is .5788 as opposed to 5.788. You did however use .5788 when calculating A*2, so I think you just wrote it wrong in the matrix.

1. tutorpaul says:

You are correct, it was just a copy error! The value that should appear in the Modal mass matrix is 0.5788

2. Trey Hicks says:

What units are the modal solutions considered?

1. tutorpaul says:

The textbook has a brief discussion of the units for modal systems on page 109 (10th edition) at the bottom of the first column. Apparently, the units for $q$ ought to be $\textrm{m}\sqrt{\textrm{kg}}$. Note that the units for $q$ will depend on whether normalization is performed on the matrix of eigenvectors.