You are Here: Home >< Physics

Resultant field

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. For this problem, shall I use cosine rule to work it out? Is it right?

2. (Original post by Daniel Atieh)
For this problem, shall I use cosine rule to work it out? Is it right?
The cosine rule is used to determine the lengths of sides of triangles, not a point. And those lengths are given. They are the distances to B.

I would rather regard the distances as a radius from a charge to the point B. If you have given the radius, you are able to calculate the electric field:

E = k*Q/r²

If you get the electrical field out, you can calculate the electrical field strength:

F = q * E = q * k*Q/r².*

That would be my way to determine the electrical field strength at B. I am not sure, if my considerations are right. ***
**
3. (Original post by Kallisto)
The cosine rule is used to determine the lengths of sides of triangles, not a point. And those lengths are given. They are the distances to B.

I would rather regard the distances as a radius from a charge to the point B. If you have given the radius, you are able to calculate the electric field:

E = k*Q/r²

If you get the electrical field out, you can calculate the electrical field strength:

F = q * E = q * k*Q/r².*

That would be my way to determine the electrical field strength at B. I am not sure, if my considerations are right. ***
**
Hi,

I hope that I misunderstand your posting. You mention that electric field strength as
F = q * E = q * k*Q/r².

I am interpreting that you are saying electric field strength is F. If this is really the case, I am afraid to say that you are wrong.

Electric field strength is F/q which is E.
4. (Original post by Eimmanuel)
Hi,

I hope that I misunderstand your posting. You mention that electric field strength as
F = q * E = q * k*Q/r².

I am interpreting that you are saying electric field strength is F. If this is really the case, I am afraid to say that you are wrong.

Electric field strength is F/q which is E.
Yeah, I have regarded the electrical field strength as F. Don't be afraid. I appreciate that you are correcting me. I am not perfect. Anything else what is wrong?
5. (Original post by Kallisto)
Yeah, I have regarded the electrical field strength as F. Don't be afraid. I appreciate that you are correcting me. I am not perfect. Anything else what is wrong?
Yes...

(Original post by Kallisto)
The cosine rule is used to determine the lengths of sides of triangles, not a point. And those lengths are given. They are the distances to B.
I think what Daniel had drawn were to represent the electric field vectors instead of the distances between the charges and point B.
So using cosine rule is perfectly good for this problem.
6. (Original post by Eimmanuel)
Yes...

I think what Daniel had drawn were to represent the electric field vectors instead of the distances between the charges and point B.
So using cosine rule is perfectly good for this problem.
Allright. So I have misunderstand the task completely. I thanked you that you have cleared the mistake. That was most kind of you.

Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: September 21, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

How does exam reform affect you?

From GCSE to A level, it's all changing

Who would you like to thank?

Poll
Study resources

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE

Reputation gems: You get these gems as you gain rep from other members for making good contributions and giving helpful advice.