What is the dot product of 5i and 8j?

1 Answer
Dec 13, 2016

Answer:

#0#

Explanation:

A property of the scaler (or dot) product is that it is zero if the vectors are perpendicular which #5ulhati# and #8ulhatj# clearly are, so without any calculation we know the answer is zero.

We can show this if required:

Let #vec u=5 ulhati+0 ulhatj=((5),(0))#
and #vec v=0 ulhati+8 ulhatj=((0),(8))#

The scaler product is:

# vec u * vec v = ((5),(0)) * ((0),(8))#
# \ \ \ \ \ \ \ \ \ \ = (5)(0) + (0)(8)#
# \ \ \ \ \ \ \ \ \ \ = 0+0#
# \ \ \ \ \ \ \ \ \ \ = 0#