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

Electric field/charge woed problem

  • Thread starter Dx
  • Start date

Dx

A copper peny has a mass 3g. A total of 4 x 10^12 electrons are transferred from one neutral penny to another. If the lectrostatic force of attraction between the pennies is equal to the weight of a penny, what is the separatio between them?

what do i do here, i donno where to begin?

Dx :wink:
 

Tom Mattson

Staff Emeritus
Science Advisor
Gold Member
5,475
20
The problem pretty much tells you what to do. You are told the charge on each penny, so you should be able to set up the expression for the electric force between them (the separation r is unknown). You are also told the mass of a penny, so you should be able to calculate the weight.

Finally, you are told that the electric force is equal to the weight. Set them equal and solve for r.
 

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