Question

What can be said about two vectors whose cross product is the zero vector?

Answer 1

they are parallel

Answer 2

since the cross product involves the cosine function. Cos(180) = 0 :)

Answer 3

*** cos(90) = 0 my mistake

Answer 4

Good lord.

xross product is a sine function, if it is zero, the angle is zero or 180, so they are in the same or opposite directions.