 #1
Riman643
 55
 2
 Homework Statement:
 The figure shows an arrangement of 15 identical disks that have been glued together in a rodlike shape of length L = 1.6900 m and (total) mass M = 104.0 mg. The arrangement can rotate about a perpendicular axis through its central disk at point O. (a) What is the rotational inertia of the arrangement about that axis? Give your answer to four significant figures. (b) If we approximated the arrangement as being a uniform rod of mass M and length L, what percentage error would we make in using the formula in Table 102e to calculate the rotational inertia?
 Relevant Equations:

I = 1/12 ML^2
I = 1/2 mr^2
This question is ridiculously complex for me. I know how to find the Inertia if it was a rod
##I =\frac{1}{12} ML^{2} = \frac{1}{12}(0.000104)(1.6900)^2 =0.00002475 kg * m^2##
To find the Inertia for the individual disks I am having trouble. Not sure how to add them all up together. Guidance would be greatly appreciated.
##I =\frac{1}{12} ML^{2} = \frac{1}{12}(0.000104)(1.6900)^2 =0.00002475 kg * m^2##
To find the Inertia for the individual disks I am having trouble. Not sure how to add them all up together. Guidance would be greatly appreciated.