This task is about reading the given passage and construct a question about the information present in the passage. Construct a question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) its answer is a continuous text span from the paragraph. Avoid creating questions that (i) can be answered correctly without actually understanding the paragraph and (ii) uses same words or phrases given in the passage.
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Question: This means that in a closed system of particles, there are no internal forces that are unbalanced. That is, the action-reaction force shared between any two objects in a closed system will not cause the center of mass of the system to accelerate. The constituent objects only accelerate with respect to each other, the system itself remains unaccelerated. Alternatively, if an external force acts on the system, then the center of mass will experience an acceleration proportional to the magnitude of the external force divided by the mass of the system.:19-1

Answer: What experiences acceleration when external force is applied to a system?


Question: Up to the 1990s, the Federal District was the most populous federal entity in Mexico, but since then its population has remained stable at around 8.7 million. The growth of the city has extended beyond the limits of the Federal District to 59 municipalities of the state of Mexico and 1 in the state of Hidalgo. With a population of approximately 19.8 million inhabitants (2008), it is one of the most populous conurbations in the world. Nonetheless, the annual rate of growth of the Metropolitan Area of Mexico City is much lower than that of other large urban agglomerations in Mexico, a phenomenon most likely attributable to the environmental policy of decentralization. The net migration rate of the Federal District from 1995 to 2000 was negative.

Answer: How many people live in the Federal District? 


Question: The university owns several centers around the world used for international studies and research, conferences abroad, and alumni support. The university has had a presence in London, England, since 1968. Since 1998, its London center has been based in the former United University Club at 1 Suffolk Street in Trafalgar Square. The center enables the Colleges of Arts & Letters, Business Administration, Science, Engineering and the Law School to develop their own programs in London, as well as hosting conferences and symposia. Other Global Gateways are located in Beijing, Chicago, Dublin, Jerusalem and Rome.

Answer:
In what year did Notre Dame first have a facility in England?