galileo's formula calculus

Galileo's formula (for falling objects) gives the position of a falling object at time t. Find the formula and use it to figure out how long it would take for an apple dropped from the restaurant at the top of the Space Needle to reach the ground. What would be its velocity when it hits the ground? (The restaurant is 500 feet from the ground.) Explain clearly and completely your work. Cite and give references for all sources you use.