Posted by Bill on Monday, October 12, 2009 at 2:36am.
A stone, initially at rest, is dropped from the top of a building. On its way down, it passes a window that is 2.52m tall. It takes 0.134 seconds to pass the window. From how far above the top of the window was the stone dropped?

Physics  drwls, Monday, October 12, 2009 at 6:41am
Let H be the distance from the top of the building to the top of the window.
Let T be the time for the stone to reach that point. g = 9.91 m/s^2
Here is what you knmow:
H = (1/2) g T^2
H + 2.25 = (1/2) g (T + 0.134)^2
Combining the two equations, you can eliminate H
2.25 = (1/2) g [0.268 T + 0.018]
Solve that for T; then compute H with one of the original equations.