Answer:
yi = Initial height of the helicopter
yf = final height of the helicopter
vyi = component of the initial vertical velocity of the helicopter
g = gravity constant (9.8m/s^2)
yf = yi + vyideltat - 1/2gt^2
0m = 1000m + (15m/2)deltat - 1/2(9.8m/s^2)t^2
-1000m = (15m/s)t - (-4.9m/s^2)t^2
Use the quadratic formula
4.8t^2 - 15t - 1000 = 0
t1 = 15.75s and t2 = -12.65
t2 is rejected, time can't be negative
Thus, it takes 15.75s before the package strikes the ground.
