Find the rotational inertia of a rod about a pivot

In summary, the conversation is about finding the rotational inertia of a rod about a pivot, given its mass and length. The pivot is located at a distance of L/3 from the left end of the rod. The person is seeking help in finding the rotational inertia and someone suggests using the parallel-axis theorem.
  • #1
Kelseywelsey
3
0

Homework Statement



i need to find the rotational inertia of a rod about a pivot. The rod is of mass M and length L and is attached to a pivot of negligible friction located at a distance of L/3 from the left end of the rod.

Homework Equations





The Attempt at a Solution



i know that if the pivot were in the center it would be (1/12)ML and if the pivot were on the end it would be (1/3)ML, but i don't know how to find it at (L/3). can anyone help me? id really appreciate it! thanks.
 
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  • #2
Try the parallel-axis theorem.
 
  • #3
thanks, ill try it!
 

1. What is rotational inertia?

Rotational inertia, also known as moment of inertia, is a measure of an object's resistance to changes in its rotational motion. It depends on the mass of the object and how the mass is distributed around the axis of rotation.

2. How do you calculate the rotational inertia of a rod?

The rotational inertia of a rod about a pivot can be calculated using the formula I = (1/3) * m * L^2, where I is the moment of inertia, m is the mass of the rod, and L is the length of the rod.

3. What is the difference between rotational inertia and mass?

Mass is a measure of an object's resistance to changes in its linear motion, while rotational inertia is a measure of an object's resistance to changes in its rotational motion. They are not directly proportional to each other, as rotational inertia also takes into account the object's shape and distribution of mass.

4. How does the pivot point affect the rotational inertia of a rod?

The pivot point, or axis of rotation, does not affect the rotational inertia of a rod. It is only used as a reference point for calculating the moment of inertia. The distribution of mass along the rod and its length are the determining factors for the rotational inertia.

5. Can the rotational inertia of a rod change?

Yes, the rotational inertia of a rod can change if the mass or length of the rod changes. Additionally, the rotational inertia can also change if the distribution of mass along the rod changes, such as adding weights to one end of the rod.

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