Final answer:
Galileo's experiment showed that objects of different masses fall at the same rate when air resistance is ignored. Therefore, both the lead ball and the glass ball would hit the ground at the same time.
Step-by-step explanation:
In Galileo's experiment, he dropped two objects of different masses from the Tower of Pisa. What he observed was that, when factors such as air resistance are ignored, all objects, regardless of their mass, experience the same acceleration due to gravity. This means that both the lead ball and the glass ball would hit the ground at the same time. This result would hold true even if the experiment was done on the Moon, where the absence of air would eliminate the effect of air resistance.