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A mass that is projected directly upwards reaches a maximum height and returns to its starting position. If air friction is significant which of the following statements is true? a. time to reach maximum height < time to return to starting position b. time to reach maximum height = time to return to starting position c. time to reach maximum height > time to return to starting position d. mechanical energy is conserved e. kinetic energy is conserved a A rocket of mass M moving through space with a velocity of v explodes into two sections. After the explosion, one of the pieces with a mass of m remains stationary in space. What is the velocity of the other piece? a. Mv / (M-m) b. Mv / (M+m) c. mv / (M-m) d. My/M e. mv/M