An object in free fall, NOT experiencing parabolic motion, has an equation of
which says:
The height of an object with respect to time in seconds is equal to the pull of gravity times time-squared plus the height from which it was dropped. Normally we use -9.8 for gravity but you said to use 10, so be it.
For us, h(t) is 5 because we are looking for the height of the window when the object is 5 m off the ground at .5 seconds;