This preview shows page 1. Sign up to view the full content.
CLASS EXERCISE #3  15 June 2005
Consider the electrical force between pairs of electric charges as shown.
These are three independent problems, with different charges but the same
separation
in each case.
represents the same number of coulombs in each
<U
case.
Let
denote the force
/
Show the magnitude (in terms of
;
J5
U
<
Þ
J
22
e.g.,
2 or 3
) and direction of the force on each charge in each pair.
JÎ
J
1.
U Š oqqqqqqqqqqqp ‹ U
<
Solution:
UŠpJ
J o‹ U
2.
2
U Š oqqqqqqqqqqqp Š U
<
Solution:
2
2
2
JoqŠ U
UŠqp J
3.
2
2
U Š oqqqqqqqqqqqp ‹ U
<
Solution:
2
4
4
2
U Š qqqp J
J oqqq ‹ U
The electrical forces are attractive (towards the other charge) in cases (1) and
This is the end of the preview. Sign up
to
access the rest of the document.
This note was uploaded on 02/11/2012 for the course PHYSICS 112 taught by Professor Fretwell during the Summer '08 term at Iowa State.
 Summer '08
 Fretwell
 Charge, Force

Click to edit the document details