---
title: "A simple Atwood’s machine remains motionless when equal masses \\(M\\) are placed on each end of the chord. When a small mass \\(m\\) is added to one side, the masses have an acceleration a. What is \\(M\\)? You may neglect friction and the mass of the cord and pulley."
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url: "https://nerd-notes.com/ubq/55190/"
date_modified: "2025-09-20T12:04:17+00:00"
---

# A simple Atwood’s machine remains motionless when equal masses \(M\) are placed on each end of the chord. When a small mass \(m\) is added to one side, the masses have an acceleration a. What is \(M\)? You may neglect friction and the mass of the cord and pulley.

A simple Atwood’s machine remains motionless when equal masses \(M\) are placed on each end of the chord. When a small mass \(m\) is added to one side, the masses have an acceleration \(a\). What is \(M\)? You may neglect friction and the mass of the cord and pulley.

- **A.** \[\frac{m(g – a)}{2a}\]
- **B.** \[\frac{2m(g – a)}{a}\]
- **C.** \[\frac{2m(g + a)}{a}\]
- **D.** \[\frac{m(g+a)}{2a}\]

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/55190/*