the height h is
h = 13 + 2.9t - 4.9t^2
so find t when h=0
A hot air balloon is traveling vertically upward at a constant speed of 2.9 m/s. When it is 13 m above the ground, a package is released from the balloon. After it is released, for how long is the package in the air? The acceleration of gravity is 9.8 m/s^2.
2 answers
h = 1/2 g t^2 + v t + h0 ... the height (h) is zero when the package lands
0 = -4.9 t^2 + 2.9 t + 13
solve the quadratic for t , the "flight time"
... you want the positive root
0 = -4.9 t^2 + 2.9 t + 13
solve the quadratic for t , the "flight time"
... you want the positive root