The duration of time for which an object stays in air is called the hang time.
For an athlete who moves 3m horizontally during a 1.25m high jump, the hang time will be the sum of the time taken by the athlete to reach the maximum height and the time taken for the athlete to reach the ground from maximum height.
Calculate the time taken t_1 by the athlete to reach the maximum height
The athlete takes same time to reach the ground from the maximum height, so
Calculate the hang time will be
Therefore the hang time of the athlete when he moves a horizontal distance of 3m is 1s.
Similarly, when the athlete runs 6m horizontally, then also there will not be a change in the hang time of the athlete as the hang time is independent of the horizontal distance covered.