a set of pulleys is used to lift a piano weighing 500 newtons. the piano is lifted 6 meters in 30 seconds. how much power is used?

How manyatoms of mercury are in 1.4214e+1 ml sample

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Dumbledore decides to gives a surprise demonstration. he starts with a hydrate of na2co3 which has a mass of 4.31 g before heating. after he heats it he finds the mass of the anhydrous compound is found to be 3.22 g. he asks everyone in class to determine the integer x in the hydrate: na2co3·xh2o; you should do this also. round your answer to the nearest integ