---
title: "A block of mass \\(m\\) is released from rest at the top of an incline of height \\(h\\) and length \\(L\\). A constant frictional force of magnitude \\(f\\) acts on the block as it slides to the bottom. Consider the following two systems:  System 1: The block and Earth. System 2: The block, Earth, and the incline.  Which of the following correctly describes the energy of these systems as the block slides from the top to the bottom of the incline?"
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url: "https://nerd-notes.com/ubq/109317/"
date_modified: "2026-03-21T23:24:02+00:00"
---

# A block of mass \(m\) is released from rest at the top of an incline of height \(h\) and length \(L\). A constant frictional force of magnitude \(f\) acts on the block as it slides to the bottom. Consider the following two systems:

System 1: The block and Earth.
System 2: The block, Earth, and the incline.

Which of the following correctly describes the energy of these systems as the block slides from the top to the bottom of the incline?

A block of mass \(m\) is released from rest at the top of an incline of height \(h\) and length \(L\). A constant frictional force of magnitude \(f\) acts on the block as it slides to the bottom. Consider the following two systems:

System 1: The block and Earth.
System 2: The block, Earth, and the incline.

Which of the following correctly describes the energy of these systems as the block slides from the top to the bottom of the incline?

![A block of mass m is positioned at the top of a ramp. The ramp has a vertical height h and a diagonal length L. A small arrow labeled v indicates the block's motion down the ramp. A force vector labeled f points up the ramp, opposite the direction of motion.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1774135442-tY2LnI.jpg)

- **A.** In System 1, the total energy is conserved because gravity is a conservative force. In System 2, the mechanical energy is conserved because the frictional force is internal to the system.
- **B.** In System 1, the mechanical energy decreases because the incline does negative work on the system. In System 2, the total energy is conserved, while the mechanical energy decreases.
- **C.** In System 1, the mechanical energy is conserved because the decrease in gravitational potential energy equals the increase in kinetic energy. In System 2, the total energy increases due to the thermal energy generated.
- **D.** In System 1, the total energy decreases because the displacement is in the same direction as the friction. In System 2, the total energy decreases because energy is dissipated as heat.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/109317/*