---
title: "A uniform rod of length \\(L\\) and mass \\(M\\) is attached to a vertical wall by a frictionless pivot. The rod is held at an angle \\(\\theta\\) relative to the wall as shown. A string is attached to the free end of the rod and pulled with a constant tension \\(T\\). The string is oriented at an angle \\(\\phi\\) above the horizontal. Which of the following expressions correctly represents the magnitude of the torque exerted by the string on the rod about the pivot?"
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url: "https://nerd-notes.com/ubq/110285/"
date_modified: "2026-04-01T04:45:39+00:00"
---

# A uniform rod of length \(L\) and mass \(M\) is attached to a vertical wall by a frictionless pivot. The rod is held at an angle \(\theta\) relative to the wall as shown. A string is attached to the free end of the rod and pulled with a constant tension \(T\). The string is oriented at an angle \(\phi\) above the horizontal. Which of the following expressions correctly represents the magnitude of the torque exerted by the string on the rod about the pivot?

A uniform rod of length \(L\) and mass \(M\) is attached to a vertical wall by a frictionless pivot. The rod is held at an angle \(\theta\) relative to the wall as shown. A string is attached to the free end of the rod and pulled with a constant tension \(T\). The string is oriented at an angle \(\phi\) above the horizontal. Which of the following expressions correctly represents the magnitude of the torque exerted by the string on the rod about the pivot?

![A vertical wall is on the left side of the frame. A pivot is attached to the wall. A thin rod of length L is attached to the pivot and hangs downwards and to the right at an angle theta measured from the vertical wall. At the end of the rod, a string is attached and pulled upwards and to the right. A dashed horizontal line is drawn through the end of the rod where the string is attached. The angle between the string and this horizontal line is phi. The setup forms a geometric configuration in the first and fourth quadrants if the pivot were the origin.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1775018739-dOjjGd.jpg)

- **A.** \( LT \sin(\theta - \phi) \)
- **B.** \( LT \sin(\theta + \phi) \)
- **C.** \( LT \cos(\theta - \phi) \)
- **D.** \( LT \cos(\theta + \phi) \)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/110285/*