Answer the following question given this paragraph: Since eddy currents and magnetic damping occur only in conductors, recycling centers can use magnets to separate metals from other materials. Trash is dumped in batches down a ramp, beneath which lies a powerful magnet. Conductors in the trash are slowed by magnetic damping while nonmetals in the trash move on, separating from the metals. (See Figure 23.17. ) This works for all metals, not just ferromagnetic ones. A magnet can separate out the ferromagnetic materials alone by acting on stationary trash. Q: Since eddy currents and magnetic damping occur only in conductors, recycling centers can use these to separate metals from other materials? Choices: - particles - cranes - alloys - magnets A:
magnets
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Answer the following question given this paragraph: The atomic weight of an element is a weighted average of its isotopes. Q: How do you determine the atomic weight of an element? Choices: - multiply protons and neutrons - subtract protons from electrons - divide protons and neutrons - add up protons and neutrons A:
add up protons and neutrons
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Answer the following question given this paragraph: Just like it sounds, a wheel and axle is composed of two connected cylinders of different diameters. Since the wheel has a larger radius (distance) than the axle, the axle will always have a larger force than the wheel. The ideal mechanical advantage of a wheel and axle is dependent on the ratio between the radii:. Q: The ratio between the radii of a wheel and axle determines what? Choices: - fundamental mechanical advantage - introduced mechanical advantage - theoretical mechanical advantage - ideal mechanical advantage A:
ideal mechanical advantage
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Answer the following question given this paragraph: DNA consists of two long chains of nucleotides. Nitrogen bases on the two chains form hydrogen bonds with each other. Adenine always bonds with thymine, and guanine always bonds with cytosine. These bonds hold the two chains together and give DNA is characteristic double helix, or spiral, shape. You can see the shape of the DNA molecule in Figure below . Sugars and phosphate groups form the "backbone" of each chain of DNA. The bonded bases are called base pairs. RNA, in contrast to DNA, consists of just one chain of nucleotides. Determining the structure of DNA was a big scientific breakthrough. You can read the interesting story of its discovery at the URL below. Q: Dna consists of how many long chains of nucleotides? Choices: - three - zero - one - two A:
two
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