# Cross Product

• Sep 12th 2008, 09:23 AM
JonathanEyoon
Cross Product
I have a concept question hopefully you guys can help me with. I was asked on a recent exam to find 3 other solutions for vector A that will make the statement true.

j x A = 2i + 3k

Since Vector <2, 0 , 3> is shown in the picture below, I used the right hand rule and curled towards x axis so that my thumb points inwards. From what I learned, this should mean that

Vector A can be

i,<2,0,0>,<3,0,0> for the statement to be true right?
• Sep 12th 2008, 09:36 AM
Plato
Recall that vector A must be perpendicular to 2i+3k.
• Sep 12th 2008, 09:48 AM
JonathanEyoon
Quote:

Originally Posted by Plato
Recall that vector A must be perpendicular to 2i+3k.

mMmMm...... I thought it was right to answer the question the way I did since whatever I cross in the xy plane from j, the resulting vector would point inwards which would be parallel to the vector <2,0,3>. Since it is parallel, whatever other vector I chose would just be a scalar multiple of it which does make the statement true....right?
• Sep 12th 2008, 11:55 AM
Plato
The cross product of two vectors is perpendicular of each of them.
$(U \times V) \bot U\,\& \,(U \times V) \bot V$ .