---
title: "An industrial motor is used to lift a crate of mass \\(M\\) vertically at a constant speed \\(v\\). The crate is lifted from the ground to a height \\(H\\) in a time interval \\(t\\). Which of the following correctly describes the average power \\(P\\) delivered by the motor to the crate and the correct justification for that power?"
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url: "https://nerd-notes.com/ubq/109180/"
date_modified: "2026-03-21T04:33:44+00:00"
---

# An industrial motor is used to lift a crate of mass \(M\) vertically at a constant speed \(v\). The crate is lifted from the ground to a height \(H\) in a time interval \(t\). Which of the following correctly describes the average power \(P\) delivered by the motor to the crate and the correct justification for that power?

An industrial motor is used to lift a crate of mass \(M\) vertically at a constant speed \(v\). The crate is lifted from the ground to a height \(H\) in a time interval \(t\). Which of the following correctly describes the average power \(P\) delivered by the motor to the crate and the correct justification for that power?

![A vertical setup showing a motor at the top of a frame connected to a pulley. A cable runs from the motor, over the pulley, and down to a rectangular crate of mass M. The crate is being lifted vertically at a constant velocity vector v pointing upward.](https://nerd-notes.com/wp-content/uploads/ubq-frq-generated/stem-fig-1-1774067623-hrVdIZ.jpg)

- **A.** The power is \(P = Mgv\) because the motor must exert an upward force of magnitude \(Mg\) to maintain a constant velocity.
- **B.** The power is \(P = Mgv\) because the net force acting on the crate must be \(Mg\) in the upward direction to keep the crate moving.
- **C.** The power is \(P = MgH\) because the work done by the motor is equal to the increase in the gravitational potential energy of the crate-Earth system.
- **D.** The power is \(P = 0\) because the work-energy theorem states that the net work done on an object moving at constant speed is zero.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/109180/*