Physlib.ClassicalMechanics.Pendulum.SlidingPendulum

The configuration space of a sliding pendulum system, which consists of a mass $m_1$ moving along a horizontal axis and a mass $m_2$ attached to $m_1$ by a string of length $l$. The configuration is characterized by the horizontal position $x_1$ of the mass $m_1$ and the angle $\phi$ of the pendulum relative to the vertical.