---
title: "An object of mass \\(m\\) is initially at rest at position \\(x = 0\\) on a horizontal frictionless surface. A single variable force given by \\(F(x) = k x^3\\) acts on the object in the positive x-direction, where \\(k\\) is a positive constant. What is the speed of the object when it reaches position \\(x = D\\)?"
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url: "https://nerd-notes.com/ubq/117541/"
date_modified: "2026-08-04T07:48:58+00:00"
---

# An object of mass \(m\) is initially at rest at position \(x = 0\) on a horizontal frictionless surface. A single variable force given by \(F(x) = k x^3\) acts on the object in the positive x-direction, where \(k\) is a positive constant. What is the speed of the object when it reaches position \(x = D\)?

An object of mass \(m\) is initially at rest at position \(x = 0\) on a horizontal frictionless surface. A single variable force given by \(F(x) = k x^3\) acts on the object in the positive x-direction, where \(k\) is a positive constant. What is the speed of the object when it reaches position \(x = D\)?

- **A.** \(D^2 \sqrt{\dfrac{k}{2m}}\)
- **B.** \(D^2 \sqrt{\dfrac{k}{4m}}\)
- **C.** \(D^2 \sqrt{\dfrac{2k}{m}}\)
- **D.** \(D^2 \sqrt{\dfrac{k}{m}}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/117541/*