---
title: "A sled is being pulled across a rough horizontal surface at a constant velocity \\(v\\) by a constant horizontal force \\(F_{pull}\\). The coefficient of kinetic friction between the sled and the surface is \\(\\mu_k\\). Which of the following correctly describes the energy of the specified system as the sled moves a distance \\(d\\)?"
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url: "https://nerd-notes.com/ubq/109192/"
date_modified: "2026-03-21T10:37:54+00:00"
---

# A sled is being pulled across a rough horizontal surface at a constant velocity \(v\) by a constant horizontal force \(F_{pull}\). The coefficient of kinetic friction between the sled and the surface is \(\mu_k\). Which of the following correctly describes the energy of the specified system as the sled moves a distance \(d\)?

A sled is being pulled across a rough horizontal surface at a constant velocity \(v\) by a constant horizontal force \(F_{pull}\). The coefficient of kinetic friction between the sled and the surface is \(\mu_k\). Which of the following correctly describes the energy of the specified system as the sled moves a distance \(d\)?

![A side view diagram of a rectangular sled on a flat horizontal floor. A horizontal arrow labeled F_pull points to the right from the center of the sled. A horizontal arrow labeled f_k points to the left from the contact point between the sled and the floor. A velocity vector v points to the right above the sled. The sled moves a displacement d to the right.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1774089474-4XFOJ4.jpg)

- **A.** The mechanical energy of the sled-only system increases because the external force \(F_{pull}\) does positive work on the sled.
- **B.** The mechanical energy of the sled-only system remains constant because the net work done on the sled by all external forces is zero.
- **C.** The total energy of the sled-and-surface system remains constant because the work done by the external pulling force is balanced by the internal friction force.
- **D.** The total energy of the sled-and-surface system decreases because the friction force converts the kinetic energy of the sled into thermal energy.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/109192/*