help me answer these questions:

Question 20 Cart X J CartY L] Trial Number Initial Velocity of Cart X (m/s) Initial Velocity of Cart Y (m/s) Final Velocity of Cart X (m/s) Final Velocity of Cart Y (m/s) L 3 -1 0.7 4.7 2 2 -2 -2 2 3 3 2 1.8 2.8 A student must conduct an experiment to verify the conservation of momentum for a closed two-cart system. Cart X and cart Y travel toward each other and eventually collide, as shown in the figure. Data collected from the experiment are shown in the table. What additional measuring tool should the student have used in order to verify the conservation of momentum? @ Force sensor Meterstick Stopwatch Balance Block X Block Y Block X and Block Y are tied together by a rope. The system containing Block X and Block Y is dropped above Earth's surface in the orientation shown in the figure. Block Y has a larger mass than Block X. Which of the following claims is correct regarding the momentum of the system containing only Block X and the system that contains Block X and Block Y? @ The system containing Block X is an open system, and the system of both blocks is an open system. The system containing Block X is an open system, and the system of both blocks is a closed system. The system containing Block X is a closed system, and the system of both blocks is an open system. @ The system containing Block X is a closed system, and the system of both blocks is a closed system. e