Principle of linear and of angular momentum

Two carts of equal weight can move along a rail with low friction. An easily rotatable disc of the same mass is mounted on each cart, to which a cord is attached. On one cart, the cord is attached to the centre of the pulley; on the other cart, the cord is wrapped around the pulley. A common weight is used to pull on both strings with a constant force over time. It is easy to observe that despite the additional rotational movement of one pulley, the centres of mass of both carts move at approximately the same speed.