Does a tomato land stem up every time?

Probably would, I'd guess. The cg is nearer the business end.

What is the cg? My daughter is doing this for a project...cant find any information on this on the web.........
thanks

Center of gravity.

I would suggest you get a lot of tomatos and a notebook. Call it first person research.

And a mop.

I call that a blasphemous waste of some potential red pasta sauce.

Depends on the shape of the tomato, for starters. Plum tomatoes are going to land on their sides e very time, I'm pretty sure. I doubt they'd ever land stem up unless you threw them in mud or something gooey and they hapened to sink in that way. Actually that probably applies to any shape of tomato--if you threw one in, for example, a bowl of yogurt, it would probably stay in whatevber position it landed, stem up or stem down. So, no, I don't think you can generalize as you do in your opening statement.

cg is center of gravity. Oh, never mind, roger answered it already.

As Roger has already explained, cg means center of gravity. Any solid object will normally hit the ground at or near its cg. (I think.) But the suggestion that you experiement and write her answer as a research project is also sound.