A small bag of sand is released from an ascending hot-air balloon whose upward constant velocity is v0 = 1.35 m/s. Knowing that at the time of the release the balloon was 81.8 m above the ground, determine the time, τ, it takes the bag to reach the ground from the moment of its release.

Answer 1

well, the height of the bag is

h(t) = 81.8 + 1.35t - 4.9t^2

so just solve for t when h=0.