- #1
danielab87
- 10
- 0
Hi I cannot get this problem for the life of me and I have no idea why
Four charges q1 = q3 = -q and q2 = q4 = +q, where q = 5 µC, are fixed at the corners of a square with sides a = 1.3 m
Calculate the x- and y-components of the net electric field at the midpoint M of the bottom side of the square.
Ok so I know that the y component is zero. So I need the x component. First I did it from q2 to q3, where i have a vector going from q2 to the midpoint, and one going from the midpoint to q3. The magnitude of the electric field of the vector from q2 to the midpoint should be kq2/(a^2/4), which i get to be about 1.1 x 10^5. Then I need to find it from the upper midpoint to q1 (the x component of the vector from q1 to the lower midpoint. This should be equal to kq1/(a^2+a^2/4)*cos(theta). I measure the theta to be 63.4 degrees using tan(theta)=a/(a/2). so i get a magnitude of about -9.5 x 10^3 here. Then i multiply each magnitude by 2 and subtract (2*-9.5 x 10^3) from (2*1.1 x 10^5) to get a total magnitude of 2.4 x 10^4 in the x direction, but this is not correct. Please tell me what I'm doing wrong here. thanks
Four charges q1 = q3 = -q and q2 = q4 = +q, where q = 5 µC, are fixed at the corners of a square with sides a = 1.3 m
Calculate the x- and y-components of the net electric field at the midpoint M of the bottom side of the square.
Ok so I know that the y component is zero. So I need the x component. First I did it from q2 to q3, where i have a vector going from q2 to the midpoint, and one going from the midpoint to q3. The magnitude of the electric field of the vector from q2 to the midpoint should be kq2/(a^2/4), which i get to be about 1.1 x 10^5. Then I need to find it from the upper midpoint to q1 (the x component of the vector from q1 to the lower midpoint. This should be equal to kq1/(a^2+a^2/4)*cos(theta). I measure the theta to be 63.4 degrees using tan(theta)=a/(a/2). so i get a magnitude of about -9.5 x 10^3 here. Then i multiply each magnitude by 2 and subtract (2*-9.5 x 10^3) from (2*1.1 x 10^5) to get a total magnitude of 2.4 x 10^4 in the x direction, but this is not correct. Please tell me what I'm doing wrong here. thanks