1. The problem statement, all variables and given/known data Consider a particle of mass m and a particle of mass 2m. They are connected by a horizontal, massless, rigid rod of length 2a. The rod is fixed to a vertical stick that connects to the rod's midpoint. The stick is spinning with constant angular speed. Consider a point P, located on the stick a distance d below the rod. Show that angular momentum of the two particle system, when taken about point P, is not conserved. 2. Relevant equations L = r X p theta = 90 degrees 3. The attempt at a solution So what I've done is find angular momentum for either mass, separately. Doing the following: L_1 = R x P = |r||p| sin(theta) = (a^2+d^2)^(1/2)* ma(omega) L_2 = R x P = |r||p| sin(theta) = (a^2+d^2)^(1/2)*2ma(omega) What I want to do... by intuition... is just add these two together. but they're magnitudes not vectors... so i am a bit confused if I can. If not, what the heck do I do?