Instegin Special Theory of Relativity - Can You Tell?

Can you tell if a closed box is travelling at a high rate of speed in some direction? In other words, in the closed box, can you tell? What if you're just going at a certain speed, without any acceleration. And i think i remember the first tu legendrepon amils um ande, the m those are. Am iss asking how yo remember all those formulas? The formula i was quoting actually, is, those are le gendre pon amils. Oh, there's a question from setor. Can you explain inertial versus non-inertial reference frames?