When I was in college, I took a class called “Modern Physics”. That was so long ago, if I told my kids that, they would think it was taught by Aristotle or Da Vinci and that the main course of study was phlogiston and the aether.
This reminds me of all those homework problems where had to give answers in mass units of electron volts per (speed of light)2.
Some guy said that E=Mc2
Energy = Mass x (speed of light)2
The rest is left as an excersize for the reader.