20 A helium atom mass 4u travels with non relativistic speed

Last updated: 6/8/2023

20 A helium atom mass 4u travels with non relativistic speed v normal to the surface of a certain material makes an elastic collision with an essentially free surface atom and leaves in the opposite direction with speed 0 6 v The atom on the surface must be an atom of O Hydrogen mass 1 u O Helium mass 4 u Carbon mass 12 u Oxygen mass 16 u Silicon mass 28 u