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A ball is tossed up in the air and it comes back down. The ball comes back down because of

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A teacher is performing a demonstration about static electricity for his class by rubbing a balloon against a wool sweater. The balloon sticks to the wool sweater. Which particles are exchanged during the demonstration?

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The continental crust floats on top of the mantle because the crust is

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Ninety-nine percent of the mass of an atom is located in