Final answer:
Masses connected by a massless string over a pulley are in a series configuration. The tension in the string is uniform throughout due to the massless and frictionless conditions, and this uniform tension aids in analyzing the dynamics of the system.
Step-by-step explanation:
The configuration of the masses connected by a massless string over a pulley is that the masses are connected in series. In the provided scenarios, the tension in the string is the same throughout because of the massless and frictionless conditions. When a string passes over a frictionless pulley and is attached to masses, the entire system accelerates uniformly, and the tension is consistent throughout the string.
For example, when two blocks are connected by a massless rope over a frictionless pulley, the acceleration of the system can be calculated by using Newton's second law and considering the net force acting on the masses due to gravity. Once the acceleration is known, the tension in the rope is determined by analyzing the forces acting on either mass. If the string is attached to a block and a hanging mass, and the system is released from rest, the speed of the hanging mass when it hits the floor can be found by using kinematic equations.
In all these cases, the important concept to remember is that the tension in a massless and frictionless system is uniform throughout the string, which facilitates the analysis of the system. This means that whether we are considering the force transmitted by the string, the mechanical advantage of a pulley system, or the calculation of a pendulum's swing, we are working with the assumption that the tension is constant along the length of the string or rope.