Why cosine theta for calculations?

[Brad_1234]

When figuring the force between 2 points, no angle the result is calculated just by distance (and charge). But when there are 3 points, either 2 charges or more and a point or 3 charges, why is there an angle calculation?

 

[Tide]

I think a good start would be to state the problem clearly. Your description of it is a bit vague.

 

[quicknote]

Cosine theta is used in calculations involving multiple points because it is a measure of the angle between two vectors. In the case of two charges, the force between them is determined solely by their distance and charge, as you mentioned. However, when there are three points involved, the angle between the vectors connecting those points becomes important in determining the force. This is because the force between two charges is a vector quantity, meaning it has both magnitude and direction. The angle between the vectors connecting the three points affects the direction of the force, and therefore must be taken into account in the calculation. Using cosine theta allows for the inclusion of this angle in the calculation, providing a more accurate result. In summary, cosine theta is used in calculations involving multiple points because it takes into account the direction of the force, which is influenced by the angle between the vectors connecting those points.