How two vectors behave if their dot product is zero

How two vectors behave if their dot product is zero

The Correct Answer and Explanation is :

If the dot product of two vectors is zero, it means that the vectors are orthogonal (perpendicular) to each other.

Explanation:

The dot product of two vectors A and B is given by:

[
A \cdot B = |A| |B| \cos(\theta)
]

where:

  • ( |A| ) and ( |B| ) are the magnitudes (lengths) of the vectors,
  • ( \theta ) is the angle between them,
  • ( \cos(\theta) ) is the cosine of that angle.

For the dot product to be zero:

[
|A| |B| \cos(\theta) = 0
]

Since the magnitudes of vectors cannot be zero unless they are zero vectors, the only way this equation holds is if:

[
\cos(\theta) = 0
]

This occurs when:

[
\theta = 90^\circ \text{ (or ( \frac{\pi}{2} ) radians)}
]

Thus, if the dot product of two vectors is zero, the angle between them is 90°, meaning they are perpendicular (orthogonal) to each other.

Why Is This Important?

  1. In Physics: Perpendicular vectors appear in force calculations, work done by a force, and electromagnetic field components.
  2. In Computer Graphics: Used in normal vector calculations to determine surface orientations.
  3. In Linear Algebra: Orthogonal vectors play a key role in vector spaces and transformations.

Below is a visual representation of two perpendicular vectors, A and B, whose dot product is zero.

The image above visually represents two perpendicular vectors A and B, originating from the same point (the origin), forming a 90-degree angle. This demonstrates that their dot product is zero, confirming their orthogonality. Let me know if you need any modifications!

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