• Support PF! Buy your school textbooks, materials and every day products via PF Here!

Calculate the amount of work required to assemble a system of charges.

  • Thread starter ditde
  • Start date
5
0
1. Homework Statement

The three charges shown below (Q1=22.6*10^-6C, Q2=22.6*10^-6C, Q3=61.0*10^-6C) are at the corners of an iscoceles triangle with sides a=4 m and b=2 m.

Q3 is 2m from Q1 and Q2, Q1 is 4m from Q2. In other words, Q3 is the point charge at the "tip" of the isosceles triangle.

Calculate the amount of work required to assemble this system of charges, assuming they are brought in from infinity.

2. Homework Equations

W = ΔPE = qΔV = q(Vi-Vf)
V = kQ/r

Being brought in from infinity means that Vi (initial voltage) = 0.

3. The Attempt at a Solution

I calculated the work required to bring in each charge individually and attempted to add them in the end.

Example of my working;

Work1 = Q1 * (0 - Vf)

Vf = kQ2/r2 + kQ3/r3

Work1 = 22.6*10^-6 * (0-(((9.10^9*22.6*10^-6)/4)+((9.10^9*61.0*10^-6)/2))
 
33,363
9,093
I calculated the work required to bring in each charge individually and attempted to add them in the end.
That is fine.
Try to work with units please, it is easier to find errors that way.
 

Related Threads for: Calculate the amount of work required to assemble a system of charges.

Replies
4
Views
8K
Replies
1
Views
1K
Replies
1
Views
2K
Replies
10
Views
3K
Replies
4
Views
16K
Replies
5
Views
2K
Replies
2
Views
139

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving
Top