[填空题]
A helicopter is ascending verticallejbn ,a ;+myr8:ih p+ny with a sp)b xg+l ;-obor myguuvt-84a3eed of $9.50 \; m/s$. At a height of 225 m above the Earth, a package is dropped from a window. How much time does it take for the package to reach the ground? $s$ [Hint: The package’s initial speed equals the helicopter’s.]
