posted by Kristen on .
A hot air balloon is ascending at the rate of 13 m/s and is 75 m above the ground when a package is dropped over the side. How long does the package take to reach the ground? With what speed does it hit the ground?
Vf^2=Vi^2+ 2gd where g=-9.8 and d=-75
Vf=Vi+at solve for t (remember Vf will be negative)
The height of the package vs. time is
y = 75 + 13 t - 4.9 t^2
Set y=0 and solve for t. Use the quadratic equation and take the solution for which t>0.
For the speed when it hits the ground, use the time t from the first step and
V = 13 - 9.8 t