Some of these are just rich.
There was one about a cannon -- if the earth is spinning eastward, then shooting a cannon ball north or south would skew the ball. The ball wouldn't land straight north (if it was shot northward).
Thing is, we're all moving on the spinning ball, as is the atmosphere.
It's like when you're in an airplane. Everyone in the airplane is moving at the same speed as the airplane, but it looks like every day life on the ground even though you're traveling hundreds of mph. From inside the plane, it's normal looking.
Most of the other "proofs" in this fall in this category. The one about the Red Bull space jump says that the guy would have landed hundred of miles away. Or that you could just go in a hot air balloon and wait and eventually the earth beneath you would spin to where you want to go.
Ok, then, how come when I jump straight up into the air, I land exactly where I jumped from? Is it flat earth, or is it that I'm moving with the earth too?
Flat earthers do not have a model that actually works. Once they have that, I'll happily inspect it, but things like cell phones and satellites just would not work with flat earth.