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The density of a substance is 4.0 g/cm3. if a sample of the substance has a volume of 25 cm3 then what is the mass

An asteroid is discovered in a nearly circular orbit around the sun, with an orbital radius that is 2.47 times earth's. what is the asteroid's orbital period, its "year," in terms of earth years?

Any color picture tube and electric field exerts a net force of magnitude 1.68x 10^-13 n on an electron the rest mass of an electron is 9.11 x 10^-13 what is the electron acceleration?