YP Atwood - Version 1.0 YP Atwood simulates a pulley (simple or double) driven by one or two suspended masses. This program is designed to study the kinematics and the dynamics of rotational motion with constant angular acceleration, and linear motion with constant acceleration. During the animation, up to 5 vectors (position, velocity, acceleration, tension and weight) and up to 7 graphs (position, velocity, acceleration, angular position, angular velocity, angular acceleration and energies vs time) can be displayed.