What happens when you drop something on the bus?

There are lots of reasons why people used to think the earth did not move. One specific arguments was that if the earth was spinning, and anybody dropped a penny, the earth would have spun about 1000 feet in the second it took for that penny to fall. Thus, the penny should land 1000 feet from you. This can be shown to be wrong by thinking about what happens if you drop something on the bus. What happens to it? And why is the penny dropping argument wrong?