What is the Constant Speed of an Elevator with a 14kW Motor and 1100kg Mass?

  • Thread starter Thread starter A.J.
  • Start date Start date
  • Tags Tags
    Energy Power
Click For Summary

Homework Help Overview

The problem involves determining the constant speed of an elevator powered by a 14kW motor, with a mass of 1100kg. The context includes the application of physics principles related to power, force, and motion.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to apply the power equation to find the elevator's speed, but questions arise regarding the accuracy of the derived speed compared to a reference value from a book.

Discussion Status

Participants are exploring the calculations and questioning the validity of the book's answer. Some suggest there may be an error in the original poster's calculations or the book's information, indicating a lack of consensus on the correct speed.

Contextual Notes

There is a mention of a potential missing factor in the calculations, and the practicality of the book's answer is questioned based on typical floor heights.

A.J.
Messages
2
Reaction score
0

Homework Statement


The motor of an elevator can produce 14kW of power, its mass is 1100kg. At what constant speed will the elevator rise?

Homework Equations


F=ma
W= Fd
P= w/t
Vav= d/t

The Attempt at a Solution


P= w/t
P= Fd/t
P= F * Vav
V= P/mg = 14000W/(1100Kg*9.8m/s^2)=1.29m/s

The book states the answer is 13m/s. I have no idea how I'm suppose to get this answer, please help. Thanks in advance.
 
Physics news on Phys.org
Hmmm, seems like there is a factor of ten missing somewhere. Are you sure you are using all the right values? Perhaps the book is wrong.
 
As you've derived, the equation P = Fv is correct, so it looks like a mistake in the book. An elevator going 13 m/s seems a bit fast if floors are approx. 5 meters apart.
 
Ok thanks guys.
 

Similar threads

How Fast Will the Elevator Rise with 14kW of Power?
  • · Replies 1 ·
Replies
1
Views
2K
What is the Average Power of an Elevator in Physics?
  • · Replies 17 ·
Replies
17
Views
2K
What is the power input of a motor pulling up an elevator?
  • · Replies 3 ·
Replies
3
Views
3K
Find the power needed to accelerate this elevator downward
  • · Replies 4 ·
Replies
4
Views
2K
When is power constant in this scenario?
  • · Replies 25 ·
Replies
25
Views
2K
A Physics 11 Elevator Work/Power Problem
  • · Replies 3 ·
Replies
3
Views
4K
Avg Power in a Rotational Energy/Work Problem
  • · Replies 6 ·
Replies
6
Views
2K
Calculate elevator acceleration using mass
  • · Replies 9 ·
Replies
9
Views
4K
Conservation of Energy Problem (Power)
  • · Replies 14 ·
Replies
14
Views
3K
What Is the Car's Speed After Exiting the Mud Patch?
  • · Replies 3 ·
Replies
3
Views
2K