---
title: "A crate of mass \\(m\\) is sliding along a horizontal warehouse floor with an initial speed \\(v\\). The floor is rough, providing a constant kinetic friction force of magnitude \\(f_k\\) on the crate. The crate slides a distance \\(d\\) before coming to a stop. Which of the following correctly describes the change in the total mechanical energy of the crate-Earth system and provides a correct justification?"
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url: "https://nerd-notes.com/ubq/109176/"
date_modified: "2026-03-21T04:33:35+00:00"
---

# A crate of mass \(m\) is sliding along a horizontal warehouse floor with an initial speed \(v\). The floor is rough, providing a constant kinetic friction force of magnitude \(f_k\) on the crate. The crate slides a distance \(d\) before coming to a stop. Which of the following correctly describes the change in the total mechanical energy of the crate-Earth system and provides a correct justification?

A crate of mass \(m\) is sliding along a horizontal warehouse floor with an initial speed \(v\). The floor is rough, providing a constant kinetic friction force of magnitude \(f_k\) on the crate. The crate slides a distance \(d\) before coming to a stop. Which of the following correctly describes the change in the total mechanical energy of the crate-Earth system and provides a correct justification?

![A rectangular block representing a crate is shown moving to the right on a horizontal line representing the floor. A velocity vector arrow points to the right. A small arrow labeled f_k points to the left to indicate the friction force.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1774067615-BA4uhA.jpg)

- **A.** The mechanical energy decreases because the kinetic friction force does negative work on the crate.
- **B.** The mechanical energy decreases because the normal force from the floor does negative work on the crate.
- **C.** The mechanical energy stays the same because the total energy of a closed system is always conserved.
- **D.** The mechanical energy stays the same because the crate is on a horizontal surface and its gravitational potential energy does not change.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/109176/*