Problem: Energy:

Examples of energy transformation include generating electric energy from heat energy via a steam turbine, or lifting an object against gravity using electrical energy driving a crane motor. Lifting against gravity performs mechanical work on the object and stores gravitational potential energy in the object. If the object falls to the ground, gravity does mechanical work on the object which transforms the potential energy in the gravitational field to the kinetic energy released as heat on impact with the ground. Our Sun transforms nuclear potential energy to other forms of energy; its total mass does not decrease due to that in itself (since it still contains the same total energy even if in different forms), but its mass does decrease when the energy escapes out to its surroundings, largely as radiant energy.

What is another example of energy transformation?
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A: lifting an object against gravity using electrical energy driving a crane motor

Problem: The Ordovician Period started at a major extinction event called the Cambrian-Ordovician extinction events some time about 485.4 1.9 Ma. During the Ordovician the southern continents were collected into a single continent called Gondwana. Gondwana started the period in the equatorial latitudes and, as the period progressed, drifted toward the South Pole. Early in the Ordovician the continents Laurentia, Siberia and Baltica were still independent continents (since the break-up of the supercontinent Pannotia earlier), but Baltica began to move toward Laurentia later in the period, causing the Iapetus Ocean to shrink between them. Also, Avalonia broke free from Gondwana and began to head north toward Laurentia. The Rheic Ocean was formed as a result of this. By the end of the period, Gondwana had neared or approached the pole and was largely glaciated.
What continent fractured off Gondwana in the direction of Laurentia?
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Answer: Avalonia

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
Hunyadi succeeded during the Siege of Belgrade in 1456 against the Ottomans, the biggest victory against that empire in decades. This battle became a real Crusade against the Muslims, as the peasants were motivated by the Franciscan monk Saint John of Capistrano, who came from Italy predicating Holy War. The effect that it created in that time was one of the main factors that helped in achieving the victory. However the premature death of the Hungarian Lord left Pannonia defenseless and in chaos. In an extremely unusual event for the Middle Ages, Hunyadi's son, Matthias, was elected as King of Hungary by the nobility. For the first time, a member of an aristocratic family (and not from a royal family) was crowned.
Who did the Hungarian nobility elect as King of Hungary?
A: Matthias

Context and question: There are many non-incandescent light sources, such as the fluorescent lamp, high-intensity discharge lamps and LED lamps, which have higher luminous efficiency, and some have been designed to be retrofitted in fixtures for incandescent lights. These devices produce light by luminescence. These lamps produce discrete spectral lines and do not have the broad "tail" of invisible infrared emissions. By careful selection of which electron energy level transitions are used, and fluorescent coatings which modify the spectral distribution, the spectrum emitted can be tuned to mimic the appearance of incandescent sources, or other different color temperatures of white light. Due to the discrete spectral lines rather than a continuous spectrum, the light is not ideal for applications such as photography and cinematography.
Why are luminescent light sources ideal for photography?
Answer: unanswerable

Question: The second approach to the problem took as its base the notion of class, and defines a set as a class which belongs to other classes, while a proper class is defined as a class which does not belong to other classes. Under the ZermeloFraenkel approach, the axioms impede the construction of a set of all sets which do not belong to themselves. In contrast, under the von Neumann approach, the class of all sets which do not belong to themselves can be constructed, but it is a proper class and not a set.
Is there an answer to this question: Under what approach does an axiom impede a set of all sets which do not belong to themselves?

Answer: ZermeloFraenkel

The Battle for Mexico City was the series of engagements from September 8 to September 15, 1847, in the general vicinity of Mexico City during the MexicanAmerican War. Included are major actions at the battles of Molino del Rey and Chapultepec, culminating with the fall of Mexico City. The U.S. Army under Winfield Scott scored a major success that ended the war. The American invasion into the Federal District was first resisted during the Battle of Churubusco on August 8 where the Saint Patrick's Battalion, which was composed primarily of Catholic Irish and German immigrants, but also Canadians, English, French, Italians, Poles, Scots, Spaniards, Swiss, and Mexican people, fought for the Mexican cause repelling the American attacks. After defeating the Saint Patrick's Battalion, the MexicanAmerican War came to a close after the United States deployed combat units deep into Mexico resulting in the capture of Mexico City and Veracruz by the U.S. Army's 1st, 2nd, 3rd and 4th Divisions. The invasion culminated with the storming of Chapultepec Castle in the city itself.
If it is possible to answer this question, answer it for me (else, reply "unanswerable"): Who commanded the U.S. Army in the battle against Mexico City?
Ah, so..
Winfield Scott