Question

Which of the following is the dot product of u = 4i + 6j – 5k and v=-10i – 8j + 10k?

Answer 1

Answer:

$\vec u\ . \ \vec v=-138$

Explanation:

Dot Product of Vectors

The dot product of two vectors is also known as scalar product. Given the vectors  

$\vec u=4\hat i+6\hat j-5\hat k$

$\vec v=-10\hat i-8\hat j+10\hat k$

The dot product is  the sum of the products of each component separately

$\vec u\ . \ \vec v=(4)(-10)+(6)(-8)+(-5)(10)$

$\vec u\ . \ \vec v=-40-48-50=-138$