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An object that is thrown straight up falls back to Earth. This is one-dimensional motion. (a) When is its velocity zero? (b) Does its velocity change direction? (c) Does the acceleration due to gravity have the same sign on the way up as on the way down? O (a) At its maximum height; (b) yes; (c) yes O (a) the velocity is never zero; (b) yes; (c) yes O (a) At its maximum height; (b) no; (c) yes (a) At its maximum height; (b) yes; (c) no (a) the velocity is never zero; (b) no; (c) yes O (a) the velocity is never zero; (b) yes; (c) no