Calculating moment of inertia for a uniform rod of mass

In summary, the formula for calculating moment of inertia for a uniform rod of mass is I = (1/12) * m * L^2, and it can be determined by using a scale or balance to weigh the rod or by multiplying the density of the material by the volume of the rod. The moment of inertia is affected by the shape of the rod, and it is important to calculate it in order to understand how the rod will behave in rotational motion. The moment of inertia cannot be negative as it is a measure of an object's resistance to changes in its rotational motion.
  • #1
Luminous Blob
50
0
I have a uniform rod of mass M, which rotates about one of its ends, and a point mass equal to the mass of the rod is added to the other end.

To calculate the new moment of inertia, do I just need to add the moment of inertia of the rod and that of the point mass together?

i.e. I = (MR^2)/3 + MR^2 ?

Any help would be much appreciated.
 
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  • #2
Yes you add them together, but make sure you add them together with respect to the same axis. Remember the parallel axis theorum.
 
  • #3
Cheers for that.
 

1. What is the formula for calculating moment of inertia for a uniform rod of mass?

The formula for calculating moment of inertia for a uniform rod of mass is I = (1/12) * m * L^2, where m is the mass of the rod and L is the length of the rod.

2. How do I determine the mass of a uniform rod?

The mass of a uniform rod can be determined by using a scale or balance to weigh the rod. Alternatively, you can also calculate the mass by multiplying the density of the material by the volume of the rod.

3. Is the moment of inertia affected by the shape of the rod?

Yes, the moment of inertia is affected by the shape of the rod. The formula for calculating moment of inertia assumes that the rod is a uniform thin rod with a circular cross-section.

4. Why is it important to calculate the moment of inertia for a uniform rod of mass?

Calculating the moment of inertia for a uniform rod of mass is important in understanding how the rod will behave when subjected to rotational motion. It is a fundamental concept in physics and engineering, and is used in various applications such as designing structural supports and calculating angular acceleration.

5. Can the moment of inertia for a uniform rod of mass be negative?

No, the moment of inertia for a uniform rod of mass cannot be negative. It is a measure of an object's resistance to changes in its rotational motion, and thus cannot have a negative value.

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