Relatively simple vectors question, but no numbers...

  • #1
6
0
The unit right now is electrostatics, but this question is really just vectors, nothing to do with charges or anything... anyways here is the info:

1. Homework Statement

Three identical point charges, A, B, and C are located as shown here:

M9bYJ9L.png


The force A-on-C is the same as the force B-on-C. What is the net force on C?

Homework Equations



I think the only equation I need is the superposition of force principle:
FnetC = FAonC + FBonC

The Attempt at a Solution


[/B]
Breaking into components (not allowed to use cosine law for some reason):

I know X-axis force is 0 as the 2 forces cancel out (since they are both equal and in opposite directions).

FnetCY = FAonC * cos(45) + FBonC * cos(45)

Not sure what else I can do though...

EDIT: I messed around with the 1-1-sqrt(2) triangle and I'm not sure if this is right, but is (2/sqrt(2)) * FAonC the right answer?

EDIT 2: Yes, that's the right answer, but sqrt(2) * FAonC is also right.

Because guess what, 2 divided by squareroot(2) is THE SAME THING AS squareroot(2)...
 
Last edited:

Answers and Replies

  • #3
182
19
assuming the charges on the charges on the corners A and B are all the same polarity
 
  • #4
6
0
assuming the charges on the charges on the corners A and B are all the same polarity

Yeah they are all identical.

seems okay to me

How would I use the 1-1-squareroot2 triangle to simplify it more? I'm not sure how to do that part too well.
 
  • #5
182
19
replace your cos45 statement with the equivalent ratio
 

Related Threads on Relatively simple vectors question, but no numbers...

  • Last Post
Replies
4
Views
1K
  • Last Post
Replies
7
Views
2K
  • Last Post
Replies
11
Views
1K
  • Last Post
Replies
15
Views
2K
  • Last Post
Replies
8
Views
2K
  • Last Post
Replies
1
Views
5K
  • Last Post
Replies
6
Views
18K
  • Last Post
Replies
9
Views
5K
  • Last Post
Replies
6
Views
14K
  • Last Post
Replies
1
Views
728
Top