Why does the modern model use an electron cloud?

What properties of a moving object are used in determining the object's energy of motion

What is the orbital period of a spacecraft in a low orbit near the surface of mars? the radius of mars is 3.4×106m.

On a geologic map, if the contacts between sedimentary rock units form a bull’s-eye pattern of concentric circles, with the youngest unit in the center, the underlying structure is a(n)