This task is about writing a correct answer for the reading comprehension task. Based on the information provided in a given passage, you should identify the shortest continuous text span from the passage that serves as an answer to the given question. Avoid answers that are incorrect or provides incomplete justification for the question.
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Question: Passage: Modern electrification systems take AC energy from a power grid which is delivered to a locomotive and converted to a DC voltage to be used by traction motors. These motors may either be DC motors which directly use the DC or they may be 3-phase AC motors which require further conversion of the DC to 3-phase AC (using power electronics). Thus both systems are faced with the same task: converting and transporting high-voltage AC from the power grid to low-voltage DC in the locomotive. Where should this conversion take place and at what voltage and current (AC or DC) should the power flow to the locomotive? And how does all this relate to energy-efficiency? Both the transmission and conversion of electric energy involve losses: ohmic losses in wires and power electronics, magnetic field losses in transformers and smoothing reactors (inductors). Power conversion for a DC system takes place mainly in a railway substation where large, heavy, and more efficient hardware can be used as compared to an AC system where conversion takes place aboard the locomotive where space is limited and losses are significantly higher. Also, the energy used to blow air to cool transformers, power electronics (including rectifiers), and other conversion hardware must be accounted for. Question: What nowdays electrification systems can use?

Answer: DC motors which directly use the DC or they may be 3-phase AC motors

Question: Passage: The only words of Jesus on the cross in the Mark and Matthew accounts, this is a quotation of Psalm 22. Since other verses of the same Psalm are cited in the crucifixion accounts, it is often considered a literary and theological creation. Geza Vermes, however, points out that the verse is cited in Aramaic rather than the Hebrew in which it usually would have been recited, and suggests that by the time of Jesus, this phrase had become a proverbial saying in common usage. Compared to the accounts in the other Gospels, which he describes as 'theologically correct and reassuring', he considers this phrase 'unexpected, disquieting and in consequence more probable'. He describes it as bearing 'all the appearances of a genuine cry'. Raymond Brown likewise comments that he finds 'no persuasive argument against attributing to the Jesus of Mark/Matt the literal sentiment of feeling forsaken expressed in the Psalm quote'. Question: What contradiction is found in this Psalm?

Answer: verse is cited in Aramaic rather than the Hebrew

Question: Passage: Because the rotor is much lighter in weight (mass) than a conventional rotor formed from copper windings on steel laminations, the rotor can accelerate much more rapidly, often achieving a mechanical time constant under one ms. This is especially true if the windings use aluminum rather than the heavier copper. But because there is no metal mass in the rotor to act as a heat sink, even small coreless motors must often be cooled by forced air. Overheating might be an issue for coreless DC motor designs. Question: How is a coreless motor cooled?

Answer:
forced air