What is the magnitude of the electric field

[xswtxoj]

Homework Statement

Two electric charges, q1 = +21.3 nC and q2 = +11.0 nC, are located on the x-axis at x
= 0 m and x = 1.00 m, respectively. What is the magnitude of the electric field at the
point x = 0.506 m, y = 0.506 m?

 

[LowlyPion]

How would you think to approach the problem?

 

[xswtxoj]

21.3+11.0 /1 = .506/.506 ?

 

[LowlyPion]

Based on what?

 

[LowlyPion]

They want you to find the E-field vector at .506,.506.

First calculate the |E1| and |E2| based on the geometric distance to both charges.

Then separate those vectors - they are vectors - into their components.

Then add the x-components and y components separately.

Happily they only want the magnitude of the E-field - |E| - so just use Pythagoras to figure the |E| of the resulting vector.

 

[xswtxoj]

theres no angle though, so it would be .506 sin____ and .506cos___ or is it 90 or 180 degrees

 

[LowlyPion]

theres no angle though, so it would be .506 sin____ and .506cos___ or is it 90 or 180 degrees

You have the coordinates of the point.

and you know - or should know that a² + b² = c²

So ... figure it out.

 

[xswtxoj]

.506 sq + .506 sq = 574.69 then sq root = .715,

 

[LowlyPion]

.506 sq + .506 sq = 574.69 then sq root = .715,

It is .715 but your intermediate result is nonsense.

So that's the r for 1 charge.

Now figure the r for the other.

 

[xswtxoj]

21.3 sq + 11 sq= 574.7 equals 23.97 after sq rt, then take the 2 r's and add them up and tan y/x?

 

[LowlyPion]

We're looking at distances, not charges.

 

[xswtxoj]

would it be : E1= ke q1/ r sq? then E2= ke q2/r sq but how would the 2nd r be found would the x= 0, and 1 or 1, 0.506 since it for q2?

 

[LowlyPion]

They want you to find the distance from 1,0 to .506,.506 for the second charge. That triangle then is .494,.506.

 

[xswtxoj]

once i get r, i solve for e, then once i get both e's do i add them up or leave it as 2 separate answers?

 

[LowlyPion]

once i get r, i solve for e, then once i get both e's do i add them up or leave it as 2 separate answers?

Once you get the |E| (magnitude of E) then you must resolve them into their x,y components and add the components - being careful of the signs - and then determine the magnitude of the result.

They want the magnitude of the Total E field at that point.