The problem involves calculating the total moment of inertia of four rods arranged to form a square, specifically when the square is suspended from one of its corners. The lengths and masses of the rods are given as L and M, respectively, and the parallel axis theorem is mentioned as a relevant concept.
Several participants are exploring different methods to calculate the moment of inertia, with some suggesting that calculating the moment of inertia for each rod at its center first is a valid approach. There is ongoing clarification regarding the distances involved and how to apply the parallel axis theorem correctly, with no explicit consensus reached yet.
Participants express confusion over the distances to be used in calculations, particularly for the bottom rods, and there is mention of the need to account for the total mass of the square when applying the parallel axis theorem.
makyol said:Does it make sense firstly finding all of four rods moment of inertia at its centre then taking it and finding the new moment of inertia secondly at the corner of square?
Actually i cannot understand precisely, can you please be more clear?
rock.freak667 said:Sorry, I didn't see the hanging from the corner part.
I=(1/12)ML2.
You need to find the distances of the centres of each rod to the corner and then use the parallel axis theorem. Then just simply add them up.
Md^2 = M(5/4)L^2makyol said:Again what distance i will use?
L or squareroot of M(5/4)L^2 ?
This approach would work. The moment of inertia about the center of the square would work out to be 4/3 ML^2. Then you can apply the parallel-axis theorem to the square as a whole. You just have to be a little careful with this step because the mass of the square is 4M, not just M.makyol said:Does it make sense firstly finding all of four rods moment of inertia at its centre then taking it and finding the new moment of inertia secondly at the corner of square?