QUES: Matter may be converted to energy (and vice versa), but mass cannot ever be destroyed; rather, mass/energy equivalence remains a constant for both the matter and the energy, during any process when they are converted into each other. However, since is extremely large relative to ordinary human scales, the conversion of ordinary amount of matter (for example, 1 kg) to other forms of energy (such as heat, light, and other radiation) can liberate tremendous amounts of energy (~ joules = 21 megatons of TNT), as can be seen in nuclear reactors and nuclear weapons. Conversely, the mass equivalent of a unit of energy is minuscule, which is why a loss of energy (loss of mass) from most systems is difficult to measure by weight, unless the energy loss is very large. Examples of energy transformation into matter (i.e., kinetic energy into particles with rest mass) are found in high-energy nuclear physics.

Why is a gain of energy difficult to measure by weight?
What is the answer?
ANS: unanswerable
QUES: In 2001, Apple introduced Mac OS X, based on Darwin and NEXTSTEP; its new features included the Dock and the Aqua user interface. During the transition, Apple included a virtual machine subsystem known as Classic, allowing users to run Mac OS 9 applications under Mac OS X 10.4 and earlier on PowerPC machines. Apple introduced Mac OS X 10.8 in February, and it was made available in the summer of 2012. Mountain Lion includes many new features, such as Mission Control, the Mac App Store (available to Mac OS X v10.6.6 "Snow Leopard." users by software update), Launchpad, an application viewer and launcher akin to the iOS Home Screen, and Resume, a feature similar to the hibernate function found in Microsoft Windows. The most recent version is OS X El Capitan . In addition to Mavericks, all new Macs are bundled with assorted Apple-produced applications, including iLife, the Safari web browser and the iTunes media player. Apple introduced Mavericks at WWDC 2013 in June, and released it on October 15 of that year. It is free of charge to everyone running Snow Leopard or later and is compatible with most Macs from 2007 and later. Mavericks brought a lot of the iOS apps, functions, and feel to the Mac as well as better multi display support, iBooks, Maps, app nap, and other upgrades to improve performance and battery life.

What computers is Maverick incompatible with?
What is the answer?
ANS: unanswerable
QUES: The U.S., UK, France, Italy and the majority of other Western countries considered the annexation of Estonia by the USSR illegal. They retained diplomatic relations with the representatives of the independent Republic of Estonia, never de jure recognised the existence of the Estonian SSR, and never recognised Estonia as a legal constituent part of the Soviet Union. Estonia's return to independence became possible as the Soviet Union faced internal regime challenges, loosening its hold on the outer empire. As the 1980s progressed, a movement for Estonian autonomy started. In the initial period of 19871989, this was partially for more economic independence, but as the Soviet Union weakened and it became increasingly obvious that nothing short of full independence would do, Estonia began a course towards self-determination.

What institution did Western countries refuse to recognize?
What is the answer?
ANS:
the Estonian SSR