Here is a question about this article: In the late 1960s, the term heavy metal was used interchangeably with hard rock, but gradually began to be used to describe music played with even more volume and intensity. While hard rock maintained a bluesy rock and roll identity, including some swing in the back beat and riffs that tended to outline chord progressions in their hooks, heavy metal's riffs often functioned as stand-alone melodies and had no swing in them. Heavy metal took on "darker" characteristics after Black Sabbath's breakthrough at the beginning of the 1970s. In the 1980s it developed a number of subgenres, often termed extreme metal, some of which were influenced by hardcore punk, and which further differentiated the two styles. Despite this differentiation, hard rock and heavy metal have existed side by side, with bands frequently standing on the boundary of, or crossing between, the genres.
What is the answer to this question: By the late 60s, what term was synonymous with hard rock?
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So... heavy metal

Here is a question about this article: Historically, AC motors were used for single or double speed elevator machines on the grounds of cost and lower usage applications where car speed and passenger comfort were less of an issue, but for higher speed, larger capacity elevators, the need for infinitely variable speed control over the traction machine becomes an issue. Therefore, DC machines powered by an AC/DC motor generator were the preferred solution. The MG set also typically powered the relay controller of the elevator, which has the added advantage of electrically isolating the elevators from the rest of a building's electrical system, thus eliminating the transient power spikes in the building's electrical supply caused by the motors starting and stopping (causing lighting to dim every time the elevators are used for example), as well as interference to other electrical equipment caused by the arcing of the relay contactors in the control system.
What is the answer to this question: What is a known advantage of the MG set?
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So... electrically isolating the elevators from the rest of a building's electrical system

Here is a question about this article: Muammar Muhammad Abu Minyar al-Gaddafi (Arabic: Arabic pronunciation: [muamar al.qaafi]; /mo.mr dfi/; audio (helpinfo); c.1942 20 October 2011), commonly known as Colonel Gaddafi,[b] was a Libyan revolutionary, politician, and political theorist. He governed Libya as Revolutionary Chairman of the Libyan Arab Republic from 1969 to 1977 and then as the "Brotherly Leader" of the Great Socialist People's Libyan Arab Jamahiriya from 1977 to 2011. Initially ideologically committed to Arab nationalism and Arab socialism, he came to rule according to his own Third International Theory before embracing Pan-Africanism and serving as Chairperson of the African Union from 2009 to 2010.
What is the answer to this question: What was the official name of Libya between 1969 and 1977?
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So...
Libyan Arab Republic