That's not true at all. Most currencies are controlled by central banks who actively maintain them to reduce volatility and risk. It's not because of mass or

That's not true at all. Most currencies are controlled by central banks who actively maintain them to reduce volatility and risk. It's not because of mass or momentum or some other physics term. Cryptocurrency by design doesn't have this and will always be open to speculators or other rational bad actors manipulating their asset markets.