This is a single rigid-bar pendulum mounted on a cart. The bar has a length of 1 m. The mass of the bar and cart can be selected. The cart has a mass of 3 kg. Set the initial (θ) then release the pendulum. Total energy is supposed to be conserved (without damping), but numerical truncation causes the total energy to deviate. There are three integration schemes to try - Euler, Symplectic (Leapfrog), and 4th-order Runge-Kutta. Set the GRAPH option to TRACE to observe the path traced by the bar.