---
title: "An elevator cab of mass \\(1000\\text{ kg}\\) is lifted vertically at a constant speed of \\(2.0\\text{ m/s}\\) by a cable connected to an overhead motor. As the cab ascends, a constant retarding frictional force of \\(4000\\text{ N}\\) opposes its motion. What is the instantaneous power delivered by the motor to the cab?"
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url: "https://nerd-notes.com/ubq/120656/"
date_modified: "2026-08-23T04:42:30+00:00"
---

# An elevator cab of mass \(1000\text{ kg}\) is lifted vertically at a constant speed of \(2.0\text{ m/s}\) by a cable connected to an overhead motor. As the cab ascends, a constant retarding frictional force of \(4000\text{ N}\) opposes its motion. What is the instantaneous power delivered by the motor to the cab?

An elevator cab of mass \(1000\text{ kg}\) is lifted vertically at a constant speed of \(2.0\text{ m/s}\) by a cable connected to an overhead motor. As the cab ascends, a constant retarding frictional force of \(4000\text{ N}\) opposes its motion. What is the instantaneous power delivered by the motor to the cab?

![A schematic diagram of an elevator cab. A rectangular box representing the cab is centered in the frame. A single vertical solid line representing the supporting cable extends from the center of the top edge of the box straight upward toward a small circular pulley at the top. To the right of the rectangular box, an upward-pointing vertical arrow is labeled v. The mass of the box is indicated by the label m placed inside the box. No other labels, lines, text, or axes appear.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1787460150-syrqIM.jpg)

- **A.** \(8.0 \times 10^3\text{ W}\)
- **B.** \(2.0 \times 10^4\text{ W}\)
- **C.** \(2.8 \times 10^4\text{ W}\)
- **D.** \(3.6 \times 10^4\text{ W}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/120656/*