SlideShare a Scribd company logo
1 of 1
Download to read offline
A man accidentally let his parakeet out the door. The bird flew up to a power line and sat there.
Unable to coax the bird down, the man stands on an aluminium ladder and reaches for the bird
with an aluminium pole. Is there any potential danger in this situation? If so, what, and if not,
why not? (Figure adapted from: Irwin, J. D. & Kerns, D. v. (1995). Introduction to Electrical
Engineering. Upper Saddle River, NJ: Prentice-Hall.)
Solution
Yes there a potentially fatal scenario because here the man may provide a path to ground from
the power line through his body. Since aluminium pole is a conductor so as soon as the man
touches power line there there will be a electrical path produced through him and power passes
from pole to man and then to ground.

More Related Content

More from footstatus

Water is essential to all living organisms. Discuss THREE properties .pdf
Water is essential to all living organisms. Discuss THREE properties .pdfWater is essential to all living organisms. Discuss THREE properties .pdf
Water is essential to all living organisms. Discuss THREE properties .pdffootstatus
 
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdf
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdftree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdf
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdffootstatus
 
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdf
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdfThe plant pathogen Xylella fastidiosa is a gram negative that attach.pdf
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdffootstatus
 
The region labeled with the letter B is transcribed into mRNA True.pdf
The region labeled with the letter B is transcribed into mRNA  True.pdfThe region labeled with the letter B is transcribed into mRNA  True.pdf
The region labeled with the letter B is transcribed into mRNA True.pdffootstatus
 
The positron decay of 15 o goes directly to the ground state of,15 N;.pdf
The positron decay of 15 o goes directly to the ground state of,15 N;.pdfThe positron decay of 15 o goes directly to the ground state of,15 N;.pdf
The positron decay of 15 o goes directly to the ground state of,15 N;.pdffootstatus
 
a) What is the Chromosome Theory of Inheritance and how was it deter.pdf
a) What is the Chromosome Theory of Inheritance and how was it deter.pdfa) What is the Chromosome Theory of Inheritance and how was it deter.pdf
a) What is the Chromosome Theory of Inheritance and how was it deter.pdffootstatus
 
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdf
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdfQuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdf
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdffootstatus
 
provide a brief definition of self assemblySolutionMolecular s.pdf
provide a brief definition of self assemblySolutionMolecular s.pdfprovide a brief definition of self assemblySolutionMolecular s.pdf
provide a brief definition of self assemblySolutionMolecular s.pdffootstatus
 
Match the Statements below with bacteriological tests. Eosin-methyle.pdf
Match the Statements below with bacteriological tests.  Eosin-methyle.pdfMatch the Statements below with bacteriological tests.  Eosin-methyle.pdf
Match the Statements below with bacteriological tests. Eosin-methyle.pdffootstatus
 
Many non-scientists have focused their criticism of evolution on the.pdf
Many non-scientists have focused their criticism of evolution on the.pdfMany non-scientists have focused their criticism of evolution on the.pdf
Many non-scientists have focused their criticism of evolution on the.pdffootstatus
 
It has been observed that F_st increases with the distance between po.pdf
It has been observed that F_st increases with the distance between po.pdfIt has been observed that F_st increases with the distance between po.pdf
It has been observed that F_st increases with the distance between po.pdffootstatus
 
Let R be an integral domain and F a field such that R is a subring of.pdf
Let R be an integral domain and F a field such that R is a subring of.pdfLet R be an integral domain and F a field such that R is a subring of.pdf
Let R be an integral domain and F a field such that R is a subring of.pdffootstatus
 
Judith, Martha, and Sophia are organizing their backpacks. While org.pdf
Judith, Martha, and Sophia are organizing their backpacks. While org.pdfJudith, Martha, and Sophia are organizing their backpacks. While org.pdf
Judith, Martha, and Sophia are organizing their backpacks. While org.pdffootstatus
 
A population of 10,000 students spends an average of $8.50 a day on .pdf
A population of 10,000 students spends an average of $8.50 a day on .pdfA population of 10,000 students spends an average of $8.50 a day on .pdf
A population of 10,000 students spends an average of $8.50 a day on .pdffootstatus
 
a local fan club surveyed 67 of its members regarding their viewing .pdf
a local fan club surveyed 67 of its members regarding their viewing .pdfa local fan club surveyed 67 of its members regarding their viewing .pdf
a local fan club surveyed 67 of its members regarding their viewing .pdffootstatus
 
A gas is a fluid. It has less molecular space and freedom of motion t.pdf
A gas is a fluid. It has less molecular space and freedom of motion t.pdfA gas is a fluid. It has less molecular space and freedom of motion t.pdf
A gas is a fluid. It has less molecular space and freedom of motion t.pdffootstatus
 
A culture of yeast was grown in a media containing sucrose labeled b.pdf
A culture of yeast was grown in a media containing sucrose labeled b.pdfA culture of yeast was grown in a media containing sucrose labeled b.pdf
A culture of yeast was grown in a media containing sucrose labeled b.pdffootstatus
 
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdf
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdfa. Dipole b. Set of a finite number of point charges c. A uniformly c.pdf
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdffootstatus
 
5. When a phosphate group is found in water a) The partially-negati.pdf
5. When a phosphate group is found in water a) The partially-negati.pdf5. When a phosphate group is found in water a) The partially-negati.pdf
5. When a phosphate group is found in water a) The partially-negati.pdffootstatus
 
Implement the additional 5 methods as indicated in the LinkedList fi.pdf
Implement the additional 5 methods as indicated in the LinkedList fi.pdfImplement the additional 5 methods as indicated in the LinkedList fi.pdf
Implement the additional 5 methods as indicated in the LinkedList fi.pdffootstatus
 

More from footstatus (20)

Water is essential to all living organisms. Discuss THREE properties .pdf
Water is essential to all living organisms. Discuss THREE properties .pdfWater is essential to all living organisms. Discuss THREE properties .pdf
Water is essential to all living organisms. Discuss THREE properties .pdf
 
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdf
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdftree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdf
tree to answer question 2. n Arabidopsis arenosa Arabidopsis halleri .pdf
 
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdf
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdfThe plant pathogen Xylella fastidiosa is a gram negative that attach.pdf
The plant pathogen Xylella fastidiosa is a gram negative that attach.pdf
 
The region labeled with the letter B is transcribed into mRNA True.pdf
The region labeled with the letter B is transcribed into mRNA  True.pdfThe region labeled with the letter B is transcribed into mRNA  True.pdf
The region labeled with the letter B is transcribed into mRNA True.pdf
 
The positron decay of 15 o goes directly to the ground state of,15 N;.pdf
The positron decay of 15 o goes directly to the ground state of,15 N;.pdfThe positron decay of 15 o goes directly to the ground state of,15 N;.pdf
The positron decay of 15 o goes directly to the ground state of,15 N;.pdf
 
a) What is the Chromosome Theory of Inheritance and how was it deter.pdf
a) What is the Chromosome Theory of Inheritance and how was it deter.pdfa) What is the Chromosome Theory of Inheritance and how was it deter.pdf
a) What is the Chromosome Theory of Inheritance and how was it deter.pdf
 
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdf
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdfQuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdf
QuestionProblem 1 In a source file carddeck.cpp, provide an impl.pdf
 
provide a brief definition of self assemblySolutionMolecular s.pdf
provide a brief definition of self assemblySolutionMolecular s.pdfprovide a brief definition of self assemblySolutionMolecular s.pdf
provide a brief definition of self assemblySolutionMolecular s.pdf
 
Match the Statements below with bacteriological tests. Eosin-methyle.pdf
Match the Statements below with bacteriological tests.  Eosin-methyle.pdfMatch the Statements below with bacteriological tests.  Eosin-methyle.pdf
Match the Statements below with bacteriological tests. Eosin-methyle.pdf
 
Many non-scientists have focused their criticism of evolution on the.pdf
Many non-scientists have focused their criticism of evolution on the.pdfMany non-scientists have focused their criticism of evolution on the.pdf
Many non-scientists have focused their criticism of evolution on the.pdf
 
It has been observed that F_st increases with the distance between po.pdf
It has been observed that F_st increases with the distance between po.pdfIt has been observed that F_st increases with the distance between po.pdf
It has been observed that F_st increases with the distance between po.pdf
 
Let R be an integral domain and F a field such that R is a subring of.pdf
Let R be an integral domain and F a field such that R is a subring of.pdfLet R be an integral domain and F a field such that R is a subring of.pdf
Let R be an integral domain and F a field such that R is a subring of.pdf
 
Judith, Martha, and Sophia are organizing their backpacks. While org.pdf
Judith, Martha, and Sophia are organizing their backpacks. While org.pdfJudith, Martha, and Sophia are organizing their backpacks. While org.pdf
Judith, Martha, and Sophia are organizing their backpacks. While org.pdf
 
A population of 10,000 students spends an average of $8.50 a day on .pdf
A population of 10,000 students spends an average of $8.50 a day on .pdfA population of 10,000 students spends an average of $8.50 a day on .pdf
A population of 10,000 students spends an average of $8.50 a day on .pdf
 
a local fan club surveyed 67 of its members regarding their viewing .pdf
a local fan club surveyed 67 of its members regarding their viewing .pdfa local fan club surveyed 67 of its members regarding their viewing .pdf
a local fan club surveyed 67 of its members regarding their viewing .pdf
 
A gas is a fluid. It has less molecular space and freedom of motion t.pdf
A gas is a fluid. It has less molecular space and freedom of motion t.pdfA gas is a fluid. It has less molecular space and freedom of motion t.pdf
A gas is a fluid. It has less molecular space and freedom of motion t.pdf
 
A culture of yeast was grown in a media containing sucrose labeled b.pdf
A culture of yeast was grown in a media containing sucrose labeled b.pdfA culture of yeast was grown in a media containing sucrose labeled b.pdf
A culture of yeast was grown in a media containing sucrose labeled b.pdf
 
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdf
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdfa. Dipole b. Set of a finite number of point charges c. A uniformly c.pdf
a. Dipole b. Set of a finite number of point charges c. A uniformly c.pdf
 
5. When a phosphate group is found in water a) The partially-negati.pdf
5. When a phosphate group is found in water a) The partially-negati.pdf5. When a phosphate group is found in water a) The partially-negati.pdf
5. When a phosphate group is found in water a) The partially-negati.pdf
 
Implement the additional 5 methods as indicated in the LinkedList fi.pdf
Implement the additional 5 methods as indicated in the LinkedList fi.pdfImplement the additional 5 methods as indicated in the LinkedList fi.pdf
Implement the additional 5 methods as indicated in the LinkedList fi.pdf
 

Recently uploaded

How to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POSHow to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POSCeline George
 
Food safety_Challenges food safety laboratories_.pdf
Food safety_Challenges food safety laboratories_.pdfFood safety_Challenges food safety laboratories_.pdf
Food safety_Challenges food safety laboratories_.pdfSherif Taha
 
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...Pooja Bhuva
 
Graduate Outcomes Presentation Slides - English
Graduate Outcomes Presentation Slides - EnglishGraduate Outcomes Presentation Slides - English
Graduate Outcomes Presentation Slides - Englishneillewis46
 
Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)Jisc
 
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptxMaritesTamaniVerdade
 
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...Nguyen Thanh Tu Collection
 
General Principles of Intellectual Property: Concepts of Intellectual Proper...
General Principles of Intellectual Property: Concepts of Intellectual  Proper...General Principles of Intellectual Property: Concepts of Intellectual  Proper...
General Principles of Intellectual Property: Concepts of Intellectual Proper...Poonam Aher Patil
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsTechSoup
 
Spellings Wk 3 English CAPS CARES Please Practise
Spellings Wk 3 English CAPS CARES Please PractiseSpellings Wk 3 English CAPS CARES Please Practise
Spellings Wk 3 English CAPS CARES Please PractiseAnaAcapella
 
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptxHMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptxmarlenawright1
 
Sociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning ExhibitSociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning Exhibitjbellavia9
 
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...ZurliaSoop
 
Understanding Accommodations and Modifications
Understanding  Accommodations and ModificationsUnderstanding  Accommodations and Modifications
Understanding Accommodations and ModificationsMJDuyan
 
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...Pooja Bhuva
 
Google Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptxGoogle Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptxDr. Sarita Anand
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17Celine George
 
ICT Role in 21st Century Education & its Challenges.pptx
ICT Role in 21st Century Education & its Challenges.pptxICT Role in 21st Century Education & its Challenges.pptx
ICT Role in 21st Century Education & its Challenges.pptxAreebaZafar22
 
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdfUnit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdfDr Vijay Vishwakarma
 
Single or Multiple melodic lines structure
Single or Multiple melodic lines structureSingle or Multiple melodic lines structure
Single or Multiple melodic lines structuredhanjurrannsibayan2
 

Recently uploaded (20)

How to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POSHow to Manage Global Discount in Odoo 17 POS
How to Manage Global Discount in Odoo 17 POS
 
Food safety_Challenges food safety laboratories_.pdf
Food safety_Challenges food safety laboratories_.pdfFood safety_Challenges food safety laboratories_.pdf
Food safety_Challenges food safety laboratories_.pdf
 
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...
Sensory_Experience_and_Emotional_Resonance_in_Gabriel_Okaras_The_Piano_and_Th...
 
Graduate Outcomes Presentation Slides - English
Graduate Outcomes Presentation Slides - EnglishGraduate Outcomes Presentation Slides - English
Graduate Outcomes Presentation Slides - English
 
Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)Accessible Digital Futures project (20/03/2024)
Accessible Digital Futures project (20/03/2024)
 
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx
2024-NATIONAL-LEARNING-CAMP-AND-OTHER.pptx
 
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
80 ĐỀ THI THỬ TUYỂN SINH TIẾNG ANH VÀO 10 SỞ GD – ĐT THÀNH PHỐ HỒ CHÍ MINH NĂ...
 
General Principles of Intellectual Property: Concepts of Intellectual Proper...
General Principles of Intellectual Property: Concepts of Intellectual  Proper...General Principles of Intellectual Property: Concepts of Intellectual  Proper...
General Principles of Intellectual Property: Concepts of Intellectual Proper...
 
Introduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The BasicsIntroduction to Nonprofit Accounting: The Basics
Introduction to Nonprofit Accounting: The Basics
 
Spellings Wk 3 English CAPS CARES Please Practise
Spellings Wk 3 English CAPS CARES Please PractiseSpellings Wk 3 English CAPS CARES Please Practise
Spellings Wk 3 English CAPS CARES Please Practise
 
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptxHMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
HMCS Vancouver Pre-Deployment Brief - May 2024 (Web Version).pptx
 
Sociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning ExhibitSociology 101 Demonstration of Learning Exhibit
Sociology 101 Demonstration of Learning Exhibit
 
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...
Jual Obat Aborsi Hongkong ( Asli No.1 ) 085657271886 Obat Penggugur Kandungan...
 
Understanding Accommodations and Modifications
Understanding  Accommodations and ModificationsUnderstanding  Accommodations and Modifications
Understanding Accommodations and Modifications
 
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...
Beyond_Borders_Understanding_Anime_and_Manga_Fandom_A_Comprehensive_Audience_...
 
Google Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptxGoogle Gemini An AI Revolution in Education.pptx
Google Gemini An AI Revolution in Education.pptx
 
How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17How to Give a Domain for a Field in Odoo 17
How to Give a Domain for a Field in Odoo 17
 
ICT Role in 21st Century Education & its Challenges.pptx
ICT Role in 21st Century Education & its Challenges.pptxICT Role in 21st Century Education & its Challenges.pptx
ICT Role in 21st Century Education & its Challenges.pptx
 
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdfUnit 3 Emotional Intelligence and Spiritual Intelligence.pdf
Unit 3 Emotional Intelligence and Spiritual Intelligence.pdf
 
Single or Multiple melodic lines structure
Single or Multiple melodic lines structureSingle or Multiple melodic lines structure
Single or Multiple melodic lines structure
 

A man accidentally let his parakeet out the door. The bird flew up to.pdf

  • 1. A man accidentally let his parakeet out the door. The bird flew up to a power line and sat there. Unable to coax the bird down, the man stands on an aluminium ladder and reaches for the bird with an aluminium pole. Is there any potential danger in this situation? If so, what, and if not, why not? (Figure adapted from: Irwin, J. D. & Kerns, D. v. (1995). Introduction to Electrical Engineering. Upper Saddle River, NJ: Prentice-Hall.) Solution Yes there a potentially fatal scenario because here the man may provide a path to ground from the power line through his body. Since aluminium pole is a conductor so as soon as the man touches power line there there will be a electrical path produced through him and power passes from pole to man and then to ground.