I am designing a pendulum impacting device for an experiment. The pendulum will impact a cart on a track. I'd like to calculate theoretical kinetic energy values for the pendulum at the point of impact. The pendulum is made of a hollow aluminum bar, with a steel plate bolted on at the bottom. I cannot neglect the weight of the bar since it has so much mass. How much of this mass is acting on the cart at the bottom? How do I calculate this? The lever arm is 45" long and theres 3" of metal above the pivot point.