Linear momentum of an object is the product of the object’s mass and velocity. Linear momentum is a vector quantity, and the direction of momentum is taken to be the direction of the object’s velocity.
or an object with mass  moving at a velocity , the angular momentum  with respect to a reference point is defined using the cross product as:
where  is the position vector of the object that describes the object’s position with respect to the reference point. The units for measuring angular momentum is kg m2 s-1. Since angular momentum is defined in terms of a cross product, the direction of the angular momentum vector is taken to be in a direction perpendicular to both the particle’s position vector  and its velocity vector .
