---
title: "Two uniform, thin rods, Rod A and Rod B, both have the same mass \\(M\\). Rod A has length \\(L\\) and Rod B has length \\(2L\\). Both rods are pivoted at one end so they can rotate in a vertical plane. The rods are held in a horizontal position and released from rest at the same time. What is the ratio \\(\\dfrac{\\alpha_B}{\\alpha_A}\\) of the magnitude of the initial angular acceleration of Rod B to that of Rod A?"
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url: "https://nerd-notes.com/ubq/111699/"
date_modified: "2026-04-14T23:59:10+00:00"
---

# Two uniform, thin rods, Rod A and Rod B, both have the same mass \(M\). Rod A has length \(L\) and Rod B has length \(2L\). Both rods are pivoted at one end so they can rotate in a vertical plane. The rods are held in a horizontal position and released from rest at the same time. What is the ratio \(\dfrac{\alpha_B}{\alpha_A}\) of the magnitude of the initial angular acceleration of Rod B to that of Rod A?

Two uniform, thin rods, Rod A and Rod B, both have the same mass \(M\). Rod A has length \(L\) and Rod B has length \(2L\). Both rods are pivoted at one end so they can rotate in a vertical plane. The rods are held in a horizontal position and released from rest at the same time. What is the ratio \(\dfrac{\alpha_B}{\alpha_A}\) of the magnitude of the initial angular acceleration of Rod B to that of Rod A?

![Two rods, A and B, are shown side-by-side. Both are horizontal and attached to a vertical wall on their left side by a pivot. Rod A is half the length of Rod B. Both are labeled with mass M. Arrows indicate they will rotate downward after release.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1776211150-VE5VdI.jpg)

- **A.** \(1/4\)
- **B.** \(1/2\)
- **C.** \(1\)
- **D.** \(2\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/111699/*