Problem 2) An electric lawn mower runs on 1000 watts of electrical power input. The same mower can cover a small yard of 2500 sq ft in 20 minutes (20 minutes is 1200 seconds). If the effective amount of energy required to cut the 2500 sq ft of grass is 420,000 joules. What is the efficiency of the electric lawnmower?
Problem 2) An electric lawn mower runs on 1000 watts of electrical power input. The same mower can cover a small yard of 2500 sq ft in 20 minutes (20 minutes is 1200 seconds). If the effective amount of energy required to cut the 2500 sq ft of grass is 420,000 joules. What is the efficiency of the electric lawnmower?
College Physics
11th Edition
ISBN:9781305952300
Author:Raymond A. Serway, Chris Vuille
Publisher:Raymond A. Serway, Chris Vuille
Chapter1: Units, Trigonometry. And Vectors
Section: Chapter Questions
Problem 1CQ: Estimate the order of magnitude of the length, in meters, of each of the following; (a) a mouse, (b)...
Related questions
Question
Transcribed Image Text:Problem 2) An electric lawn mower runs on 1000 watts of electrical power input.
The same mower can cover a small yard of 2500 sq ft in 20 minutes (20 minutes is
1200 seconds). If the effective amount of energy required to cut the 2500 sq ft of
grass is 420,000 joules. What is the efficiency of the electric lawnmower?
Problem 3) The small wheel in the picture has
a
radius of 1 inch and the large one has a radius of 8 inches. The yarn
that connects them travels at a speed of 12 inches/second. If the
small wheel rotates at 800 RPM, what is the rotational speed of the
large wheel?
Radius : 8 inches
Radius : 1 inch
Expert Solution
Step 1
Given data:
Power (P) = 1000 W
Time (t) = 20 minutes = 1200 seconds
Energy required (Eout) = 420,000 J
Required:
The efficiency of the electric lawnmower
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
Recommended textbooks for you
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
College Physics
Physics
ISBN:
9781305952300
Author:
Raymond A. Serway, Chris Vuille
Publisher:
Cengage Learning
University Physics (14th Edition)
Physics
ISBN:
9780133969290
Author:
Hugh D. Young, Roger A. Freedman
Publisher:
PEARSON
Introduction To Quantum Mechanics
Physics
ISBN:
9781107189638
Author:
Griffiths, David J., Schroeter, Darrell F.
Publisher:
Cambridge University Press
Physics for Scientists and Engineers
Physics
ISBN:
9781337553278
Author:
Raymond A. Serway, John W. Jewett
Publisher:
Cengage Learning
Lecture- Tutorials for Introductory Astronomy
Physics
ISBN:
9780321820464
Author:
Edward E. Prather, Tim P. Slater, Jeff P. Adams, Gina Brissenden
Publisher:
Addison-Wesley
College Physics: A Strategic Approach (4th Editio…
Physics
ISBN:
9780134609034
Author:
Randall D. Knight (Professor Emeritus), Brian Jones, Stuart Field
Publisher:
PEARSON