Answer:
Maximum height, h = 7.2 meters
Step-by-step explanation:
It is given that,
Initial velocity of the balloon, u = 12 m/s
At maximum its final velocity, v = 0
We have to find its maximum height. Let its maximum height is h. Using third equation of motion as :

here a = -g
So,


h = 7.2 meters
Hence, the maximum height of balloon is 7.2 meters.