Question

What is k.i?

(a) 0

(b) 1

(c) -1

(d) ∞

This question was posed to me at a job interview.

I would like to ask this question from Dot Product and Cross Product in division Force Vectors of Engineering Mechanics

Answer 1

Correct choice is (a) 0

For explanation: As the dot product of only the same Cartesian component is unity, i.e. i.i = 1 and j.j =1, rest all remaining dot product will give 0(i.j = 0 and j.k = 0). Cross product of the same plane vectors always gives zero. And dot product of the same plane vector gives a scalar quantity.