a helicopter is flying with constant horizontal velocity as it prepares to drop supplies on a roof below. the supplies land directly on target in the center of the roof. if we ignore air resistance, which statement is not true? i. the helicopter must be directly over the target when the supplies are dropped. ii. the gravitational acceleration acting on the supplies is constant. iii. the helicopter and the supplies have the same horizontal velocity when the supplies are dropped. iv. the supplies have a parabolic trajectory.