# Homework Help: Paper Jumping, Charged Comb

1. Sep 5, 2007

### eraemia

1. The problem statement, all variables and given/known data

What interactions are at play in the following scenario, and what objects are involved in the interactions?
A tiny bit of paper jumps from a tabletop toward an electrically charged comb. (Consider the bit after it has left the tabletop but before it reaches the comb.)

2. Relevant equations

Use the following interaction categories:
Gravitational, electrostatic, magnetic, friction, compression, and tension

3. The attempt at a solution

It seems that the obvious answer is an electrostatic interaction between the bit of paper and the comb. But how does this interaction affect the paper's motion? Does it suck the paper like a magnet? And while the paper is in the air, what other interactions are at play? With gravity? Compression with the air, or friction with the air?

2. Sep 5, 2007

### CEL

The negatively charged comb repels the free electrons in the paper, so the surface near the comb becomes positively charged. The negative cahrges in the comb attract yhe positive charges in the paper.
The paper is submitted to the electrostatic force, the gravitational acceleration and to friction with the air.