1D kinematics hot air balloon

Question

A hot air ballon is traveling vertically downward at a constant speed of 4.6 m/s. When it is 21 m above the ground, a small package is released from the balloon. What is the package’s velocity just before hitting the ground?

Answer 1

Equation of moution of package: y = 21 - 4.6t - 1/2gt².To get time we set y = 0.

4.9t² + 4.6t - 21 = 0, x = 1.6534 s.

Velocity v = y' = -4.6 - gt = - 4.6 - 9.8·1.6534 = - 20.82 m/s.

Minus means that velocity directed down.