The weight does not matter (Google Galileo, http://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment)
about 9.81 m/s^2
What is the acceleration of a 10-N freely falling object with no air resistance?
2 answers
http://en.wikipedia.org/wiki/Galileo%27s_Leaning_Tower_of_Pisa_experiment