7.6 - Cross Product of Two Vectors

The cross product of a x b between 2 vectors a and b results in a :

third vector that is perpendicular to the plane in which the given vectors lie

Application of cross product :

momentum and torque

L = r x P (momentum)

• L: angular momentum

• r: position vector

• P: linear momentum

What can we use to predict the direction of the cross product vector :

right hand rule

Circle with dot means:

straight out of board / page (positive x axis)

Circle with x means:

in to the board / page (negative x axis)

Any scaler multiple of resultant gives:

perpendicular vector to a and b but not equal to cross vector product

Use Pythagorean to get :

magnitude from resultant cross product