Velocity

I was standing in line at the Credit Union today watching their little closed-circuit TV broadcasting ads for their services, stock quotes, local weather and the like - and they put up a 'Factoid' that said:

"According to the Theory of Relativity, mass increases with velocity. In other words, the faster an object travels, the more mass it has."

Really?

In that case, I better start walking slower.



(I know. There are 2 kinds of 'mass: "relativistic mass" (mv) and "invariant mass" (m0.) The invariant mass of a particle is independent of its velocity v, whereas relativistic mass increases with velocity and tends to infinity as the velocity approaches the speed of light c. But that isn't what the folks at the credit union were saying!)