- #1
erisedk
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Homework Statement
There are four solid balls with their centres at the four corners of a square of side a. The mass of each sphere is m and radius is r. Find the moment of inertia of the system about one of the sides of the square.
Homework Equations
The Attempt at a Solution
I= 2 (two balls) × [ 2/5 mr^2 (Icm) + ma^2 ] (just used parallel axis theorem)
However, in the answer,
I = 2 ( 2/5 mr^2 ) + 2×[ 2/5 mr^2 + ma^2 ]
Why have they added 2 ( 2/5 mr^2 ) ??