Physics 26: Quarks are the particle constituents of protons and neutrons. Physics 28: Matter is a physics term meaning stuff or substance. Physics 30: Newtons third law says that for every action there is an equal and opposite reaction. Physics 32: CERN is a huge particle accelerator laboratory located on the border of France and Switzerland. Neutrons have no electric charge. SF stands for Swiss Francs. Physics 34: According to special relativity, the notion of time is relative in the sense that it depends on the motion of the observer. Physics 36: Observations are observer dependent. Physics 38: The general theory of relativity says that mass warps the space-time surrounding it and that curved space-time is responsible for the force of gravity. Superstring theories predict that space is nine-dimensional but that six of the dimensions curl up into a tiny, unobservable hyperspace. Radioactive elements exist in at least minute quantities in everything so that there is always low-level radiation. The protons and neutrons in a nucleus are held together by gluons. A wormhole is a tube connecting one region of spacetime to another; it is unknown whether wormholes really exist. The entropy, which is closely related to disorder, of a close system always increases with time. Atoms and molecules, which make up matter, are mostly empty space. The observation of a mixed quantum state causes it to collapse or change. Electrons move in materials (especially metals) at high speeds. If mass is converted into energy, a lot of energy is released (E=mc 2 ). The uncertainty principle says that measurement of the momentum and position of an object is restricted; the faster an object moves, the higher its momentum and the more uncertain is its location. When matter and anti-matter come together, energy is released in enormous quantities according to the formula E=mc 2 . Protons , neutrons and electrons , which are the constituents of atoms , are always the same. In quantum tunneling , an object can move through a region forbidden by classical mechanics. The second law of thermodynamics says that the entropy of the universe increase with time. A black hole is an extremely dense object whose gravity is so strong that nothing, including light, can escape from within; the pull of gravity near a black hole is enormous. Physics 42: Bar magnets have a north pole and a south pole at opposite ends. Like poles repel and unlike poles attract. Thus, when one magnet is oriented with (say) its north end facing the north end of the other, the magnets repel, but when one magnet is turned around, the two attract
Posted on: Thu, 03 Jul 2014 00:18:31 +0000
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