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UNIT VECTOR

Unit Vector

Definition Of Unit Vector

The Unit Vector of a vector v is given as  where |v| is the magnitude or norm of the vector v.

More About Unit Vector

The magnitude of a unit vector is 1
Dot product of two unit vectors is the cosine of the angle of the angle between them.

Example of Unit Vector

The unit vector in the direction of the vector v =<1, 2=""> can be found in the following way: Magnitude of the vector v =|v| = 
Unit vector in the direction of v is given as 
Hence, the unit vector in the direction of v is = 

Video Examples: Unit Vectors

Solved Example on Unit Vector

Ques: Which of the following is the unit vector in the direction of the vector v= <9, 12="">?

Choices:


Correct Answer: A

 

Solution:

Step 1: v = <9, 12="">.
Step 2: Magnitude of the vector v = |v| = = 15 [Use the formula to find the magnitude of v.]
Step 3: Unit vector in the direction of  [Write the unit vector of v] 
Step 4:= () <9, 12="">
Step 5:  

Quick Summary

  • Magnitude of a unit vector is always 1.
  • Used to represent direction.
  • Can be found by dividing a vector by its magnitude.
\[ \hat{v} = \frac{v}{|v|} \]

🍎 Teacher Insights

Emphasize the geometric interpretation of dividing by the magnitude. Use examples in 2D and 3D to illustrate the concept. Connect unit vectors to direction cosines.

🎓 Prerequisites

  • Vectors
  • Magnitude of a Vector
  • Scalar Multiplication

Check Your Knowledge

Q1: Which of the following is a unit vector in the direction of v = <9, 12>?

Q2: What is the magnitude of the unit vector?

Frequently Asked Questions

Q: How do you find a unit vector?
A: Divide the vector by its magnitude. If v = , then the unit vector is where |v| = sqrt(a^2 + b^2)

Q: What is the magnitude of a unit vector?
A: The magnitude of any unit vector is 1.

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