Horizontal and vertical component for electric field

[ToonBlue]

Homework Statement

At the video length 1:25 , why does the vertical component cancel out ?



At the video length 3:55 , why does the horizontal component cancel out?

Homework Equations

The Attempt at a Solution

I don't seem to understand this part very well for the vertical and horizontal component.

 

[Doc Al]

Symmetry. In the first case, you have a similar charge arrangement above and below the center, so their vertical effects cancel.

 

[ToonBlue]

Does it mean that if the arc is 1/4 and not 1/2 , it will have both x and y component ? since there is no symmetry ? correct me if I am wrong

 

[Doc Al]

Does it mean that if the arc is 1/4 and not 1/2 , it will have both x and y component ? since there is no symmetry ? correct me if I am wrong

I don't know what you mean. It's not the size of the arc, it's the symmetry.

 

[ToonBlue]

What I mean is something like this? In this case , it will have both x and y component since there is no symmetry. Correct or ? am i wrong?

 

[Doc Al]

What I mean is something like this? In this case , it will have both x and y component since there is no symmetry.

The symmetry will be about a line from the point O to the center of the arc. Since that's not along the x or y axis, there will be an x and y component.

 

[ToonBlue]

I see thank you.