A ball is thrown straight up from height H while a second is thrown straight down. Neglect air resistance. After the balls have been released
(a) the one thrown up has the greater acceleration.
(b) the one thrown down has the greater acceleration.
(c) the accelerations are the same.
(d) neither ball accelerates after it has been released.
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The man of mass m1 and the woman of mass m2 are standing on opposite ends of the platform of mass m0 which moves with negligible friction and is initially at rest with s = 0. the man and woman begin to approach each other. derive an expression for the displacement s of the platform when the two meet in terms of the displacement x1 of the man relative to the platform.