- #1

miyayeah

- 27

- 0

## Homework Statement

The diagram is attached. What is the strength of the electric field at the position indicated by the dot in Figure 1? What is the direction of the electric field at the position? Specify the direction as an angle measured clockwise from the positive x axis.

## Homework Equations

E=(k⋅q)/r

^{2}

## The Attempt at a Solution

To solve the first question, I calculated for the individual electric fields from each charge on the point:

E+ = [(8.99⋅10

^{9}NM

^{2}/C

^{2})(3⋅10

^{-9}C)] / (0.05m)

^{2}

= 10788 N/C

E- = [(8.99⋅10

^{9}NM

^{2}/C

^{2})(6⋅10

^{-9}C)] / (0.111803m)

^{2}]

= 4315 N/C

(0.111803 is from applying trig to the distance between the charges and point.)

Then I found the angle between the line on the y-axis and the line connecting the negative charge to the point:

Θ= tan

^{-1}(0.05/0.1) = 26°

Θ (between imaginary line on x-axis (to the right from negative charge) to the line connecting the negative charge to the point) = 90-26° = 63°

Then I tried to solve the x and y components of the electric field of the negative charge:

(cosΘ)(4315N/C) = 1929 N/C

(sinΘ)(4315N/C) = 3859 N/C

Since there is only x component for the positive charge and to solve for the net electric field at that point, I did:

√((1929 N/C + 10788 N/C)

^{2}+(3859N/C)

^{2})

I did not get the answer to the question despite trying out these steps. The correct answer is 9700 N/C. Without knowing the first half of the question I don't think I am able to answer the next half (the direction). Any help would be appreciated!