Final answer:
All tanks released by the jet planes will have the same final impact speed if air resistance is negligible, as the horizontal direction of travel does not affect the vertical velocity influenced only by gravity.
Step-by-step explanation:
When determining the impact speed of an object in free fall, only two factors need to be considered: the initial velocity and the acceleration due to gravity. In the situation described, where three different jet planes release a fuel tank at the same height and with the same initial speed but in different directions, the absence of air resistance implies that the direction of travel is irrelevant to the final impact speed.
According to the principles of physics, specifically the conservation of energy, all tanks will have the same final (impact) speed because they are only influenced by gravity, which affects all objects equally regardless of their horizontal motion. The distance traveled horizontally does not impact the final vertical velocity of each tank because the horizontal and vertical components of motion are independent in the absence of air resistance.
Hence, each tank will have the same impact speed, which is determined by the initial speed it had when released from the jet plane and the acceleration due to gravity (approximately 9.81 m/s2) acting on it as it falls to the ground.