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.

[EX Q]: 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
[EX A]: What experiences acceleration when external force is applied to a system?

[EX Q]: Muhammad Ali Pasha evolved the military from one that convened under the tradition of the corvée to a great modernised army. He introduced conscription of the male peasantry in 19th century Egypt, and took a novel approach to create his great army, strengthening it with numbers and in skill. Education and training of the new soldiers was not an option; the new concepts were furthermore enforced by isolation. The men were held in barracks to avoid distraction of their growth as a military unit to be reckoned with. The resentment for the military way of life eventually faded from the men and a new ideology took hold, one of nationalism and pride. It was with the help of this newly reborn martial unit that Muhammad Ali imposed his rule over Egypt.
[EX A]: Who modernized Egyptian army?

[EX Q]: In hydraulic elevator systems, emergency power will lower the elevators to the lowest landing and open the doors to allow passengers to exit. The doors then close after an adjustable time period and the car remains unusable until reset, usually by cycling the elevator main power switch. Typically, due to the high current draw when starting the pump motor, hydraulic elevators are not run using standard emergency power systems. Buildings like hospitals and nursing homes usually size their emergency generators to accommodate this draw. However, the increasing use of current-limiting motor starters, commonly known as "soft-start" contactors, avoid much of this problem, and the current draw of the pump motor is less of a limiting concern.
[EX A]:
How do hydraulic elevators work in emergencies?