2—how thick a wall. easy in a Japanese home

also apparently easy if you are an outfielder. a couple of them do it every season, and those walls are not thin. they stumble afterwards and fall down, but go full blast thru the wall

3—most things will bounce, but some things will just crumble

4–actually, a coyote can take off like a bat out of he… they are very fast, and have excellent acceleration

Remember that matter is made up of atoms/molecules with space in between. In an object, there’s usually much more open space than atoms. If you were to run at a wall, theoretically the atoms in your body could be lined up exactly with the empty spaces between the atoms in the wall. If no body atoms and wall atoms hit each other, you’d pass through. It’s such an unbelievably small chance of happening, but not impossible.