Matt drops a thing (6 kg) from a height (20 m) what is the maximum velocity it will reach just before it hits the ground?

The speed of light in a material is 0.50 c. what is the critical angle of a light ray at the interface between the material and a vacuum?

Consider a hydrogen atom in the ground state. what is the energy of its electron? =e= jj now consider an excited‑state hydrogen atom. what is the energy of the electron in the =5n=5 level? =e5= j

Ne way in which elements differ from each other is the structure of the electron cloud in each element's atoms. in an electron cloud, an electron that is farther away from the nucleus has