This model demonstrates a method of determining the effective inertia of a dynamic system, in this case the dynamic system is a slider-crank mechanism. Attached to the crank arm is an active sensor subsystem that performs the operation required to provide the effective inertia information. The sensor is a subsystem that works by incrementally moving a joint in the system at a constant acceleration of 1rad/s/s and then stopping. At the start of each acceleration phase, all velocities are zero and the measured torque is equal to the effective inertia.